CAD Techniques for Boat Design Competition
THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
CAD Techniques for Boat Design Competition
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
TABLE OF CONTENTS AutoCAD ........................................................................................................................................ 3 Building the Boat ........................................................................................................................ 3 UCS (User Coordinate System) .............................................................................................. 4 Polyline Edit ........................................................................................................................... 4 Region ..................................................................................................................................... 4 Extrude .................................................................................................................................... 5 Shell ........................................................................................................................................ 5 Subtract ................................................................................................................................... 5 Intersect ................................................................................................................................... 5 Separate ................................................................................................................................... 5 Union ...................................................................................................................................... 5 Weight & Center of Gravity ....................................................................................................... 6 Mass Properties ....................................................................................................................... 6 Displacement & Draft ................................................................................................................. 6 Divide...................................................................................................................................... 6 Slice ........................................................................................................................................ 6 Face/Edge Commands ............................................................................................................ 6 Section .................................................................................................................................... 7 Area ......................................................................................................................................... 7 Volume.................................................................................................................................... 7 Buoyancy .................................................................................................................................... 7 Stability ....................................................................................................................................... 7 Inventor ........................................................................................................................................... 8 Building the Boat ........................................................................................................................ 8 UCS (User Coordinate System) .............................................................................................. 8 ViewCube ............................................................................................................................... 9 Extrude .................................................................................................................................... 9 Shell ........................................................................................................................................ 9 Combine .................................................................................................................................. 9 Move Component ................................................................................................................. 10 Delete Face ........................................................................................................................... 10 Weight & Center of Gravity ..................................................................................................... 10 iProperties ............................................................................................................................. 10 Displacement & Draft ............................................................................................................... 10 Plane Commands .................................................................................................................. 10 Split ....................................................................................................................................... 11 Area ....................................................................................................................................... 11 Volume.................................................................................................................................. 11 Buoyancy .................................................................................................................................. 11 Stability ..................................................................................................................................... 11
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
AUTOCAD AutoCAD is 2D, and for the purposes of the Boat Design Competition, capable 3D, drafting software available for free student download from Autodesk. AutoCAD is widely used, and therefore help is readily available. Any additional questions may be sent to the Team Mentor. While many methods exist to provide the same result, a selection of recommended AutoCAD commands has been given. This guide is not intended to teach students AutoCAD.
Building the Boat When creating steel plates, do not union them together! Each plate needs to be entered as a separate line on the Weight tab of the Calculations Spreadsheet, so a separate center of gravity will be needed for each plate. It may be beneficial to build two versions of the boat; one completely solid (like the ship in the Illustrated Glossary) and one of the final product (with 1/8 inch thick hull plates). Either can be built first. Of course, each model can be copied several times for tinkering since some commands may alter the model.
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
UCS (User Coordinate System)
The UCS is the Cartesian coordinate system that dictates how things are drawn. 2D geometry is always drawn on the XY plane. The other two planes are used to modify 3D components. Rotate It may be necessary to rotate the UCS to reorient the XY plane. 1. Type UCS in the command line 2. Type the axis (X, Y, or Z) to be rotated about 3. Type the angle of rotation around that axis Origin It may be necessary to move the UCS (e.g. the boat was not originally constructed at the reference point). 1. Type UCS in the command line 2. Type O 3. Click the location of the new origin
Polyline Edit The polyline edit command can be used to transform a series of (closed) lines into a (closed) polyline. The 2D polyline can then be used to make 3D solids. 1. Type PEDIT in the command line 2. Select one of the lines 3. Type Y, then J 4. Select the remaining lines that are to be joined together
Region The region command can be used to transform a series of (closed) lines into a region. The region can then be used to make 3D solids. 1. Type REGION in the command line 2. Select all lines that are to make up the region
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
Extrude The extrude command can be used to give thickness to 2D polylines/regions. 1. Type EXTRUDE in the command line 2. Select the polyline or region to be extruded 3. Specify height of extrusion (or direction, path, taper angle)
Shell The shell command can be used to transform a solid into plates of discrete thickness. 1. Type SOLIDEDIT in the command line 2. Type BODY and then SHELL 3. Select the solid 4. Select the faces that are not to be offset 5. Specify the shell offset distance (1/8 for steel plate)
Subtract The subtract command can be used to remove one solid from another. 1. Type SUBTRACT in the command line 2. Select the first solid 3. Select the second solid
Intersect The intersect command can be used to create a solid from two overlapping solids. Similarly, the INTERFERE command retains the two overlapping solids as well as the new solid (uncheck the box in the INTERFERENCE CHECKING popup window). 1. Type INTERSECT in the command line 2. Select the overlapping solids
Separate When two solids are functioning as one, but are no longer physically connected, the separate command can split them apart (so that the unused solid can be deleted). 1. Type SOLIDEDIT in the command line 2. Type BODY and then SEPARATE 3. Select the solid
Union The union command can be used to combine solids. 1. Type UNION in the command line 2. Select all solids that are to be joined together
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
Weight & Center of Gravity Mass Properties Mass properties can be used to find the centroid (i.e. center of gravity) of regions/solids (i.e. hull plates). The location and orientation of the UCS in relation to the reference point is critical for this command. 1. Type MASSPROP in the command line 2. Select the object The resulting popup window will display the centroid’s distance away from the current location of the UCS.
Displacement & Draft The immersed section of the hull can be constructed by forming a prism (with dimensions equal to the boat’s length, beam, and depth) around the boat and subtracting the hull plates from the prism (then separate the disconnected solids). This results in a mold of the boat as if filled to the brim with concrete. The boat is then sliced at the draft.
Divide The divide command can be used to determine the spacing between an odd number of stations/waterplanes. Draw a line from the bow to the stern or from the keel to the design waterline (use PTYPE to change the nodes to a more visible symbol). 1. Type DIVIDE in the command line 2. Select the line 3. Specify the (even) number of division segments
Slice The slice command can be used to cut a solid into pieces. The orientation of the UCS is critical for this command. 1. Type SLICE in the command line 2. Select the solid 3. Type the plane (or define one) that will be used for slicing 4. Click a point on the plane where the slice is to be made 5. Select the side of the solid that is to be retained or press enter to retain both sides
Face/Edge Commands Face/Edge commands can be used to copy faces/edges of solids. 1. Type SOLIDEDIT in the command line 2. Type FACE/Edge and then COPY 3. Select the face/edge to be copied
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
Section The section command can be used to extract a region from a solid. The resulting section is a region. 1. Type SECTION in the command line 2. Select the solid 3. Type the plane (or define one) that will be used for sectioning 4. Click a point on the plane where the section is to be made
Area The area command can be used to quantify areas. If the command is used on a solid, the entire surface area will be calculated. Likewise, if the command is used on a region/plane/face/surface, the area of “one” side will be calculated. Alternatively, the MASSPROP command can be used. 1. Type MEASUREGEOM in the command line 2. Type AREA 3. Select object or specify area by clicking corners
Volume The volume command can be used to quantify volumes (i.e. volumetric displacement when the hull is sliced at the desired draft). Alternatively, the MASSPROP command can be used. 1. Type MEASUREGEOM in the command line 2. Type VOLUME 3. Select solid
Buoyancy For the center of buoyancy, the mass properties command can be used on the immersed section of the hull that was used to find the volumetric displacement since the center of buoyancy is the centroid of the immersed section. For the longitudinal center of flotation, the mass properties command can be used on the design waterplane area since the longitudinal center of flotation is the centroid of that area.
Stability The mass properties command can be used on the design waterplane area (region) to find the moments of inertia. If the “area” is not two dimensional, the mass moments of inertia display. The area must be located on the XY plane. In accordance with the Guidelines, X is needed for the transverse moment of inertia and Y (parallel axis theorem permitting) is needed for the longitudinal moment of inertia. If the area is symmetrical, the PRINCIPAL MOMENTS can be used without relocating the UCS.
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
INVENTOR Inventor is 3D drafting software available for free student download from Autodesk. Inventor is widely used, and therefore help is readily available. Any additional questions may be sent to the Team Mentor. While many methods exist to provide the same result, a selection of recommended Inventor commands has been given. This guide is not intended to teach students Inventor.
Building the Boat When creating steel plates, do not union them together! Each plate needs to be entered as a separate line on the Weight tab of the Calculations Spreadsheet, so a separate center of gravity will be needed for each plate. Instead of letting the 3D MODEL commands default to JOIN, choose NEW SOLID instead. It may be beneficial to build two versions of the boat; one completely solid (like the ship in the Illustrated Glossary) and one of the final product (with 1/8 inch thick hull plates). Either can be built first. Of course, each model can be copied several times for tinkering since some commands may alter the model.
UCS (User Coordinate System)
The UCS is the Cartesian coordinate system that dictates how things are drawn. 2D geometry is drawn on the XY, YZ, and XZ planes. 8
THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
ViewCube
Reorient the ViewCube so that construction can be in accordance with the reference point (ignore that the boat’s port side will be RIGHT on the ViewCube). 1. Orbit the drawing so that UCS is displayed as shown above 2. Click the corner of the ViewCube that is presently highlighted 3. Hover over the ViewCube and right click on the HOME symbol 4. Select SET CURRENT VIEW AS HOME FIT TO VIEW 5. Select the YZ plane of the ViewCube (LEFT) 6. Hover over the ViewCube and right click on the HOME symbol 7. Select SET CURRENT VIEW AS FRONT
Extrude The extrude command can be used to give thickness to 2D sketches. 1. Click EXTRUDE on the 3D Model tab of the ribbon 2. Select the sketch to be extruded 3. Specify height of extrusion (or direction, taper angle) and NEW SOLID
Shell The shell command can be used to transform a solid into plates of discrete thickness. 1. Click SHELL on the 3D Model tab of the ribbon 2. Select the faces that are not to be offset 3. Specify the shell thickness (1/8 for steel plate)
Combine The combine command can be used to subtract one solid from another, union two solids, or create a solid from the intersection of two solids. 1. Click COMBINE on the 3D Model tab of the ribbon 2. Select either JOIN, CUT, or INTERSECT 3. Select the two solids in order of operation
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
Move Component Unlike AutoCAD, the global/world UCS cannot be moved. Instead, the model’s reference point must be moved to the assembly’s origin in accordance with the Guidelines. In an assembly file: 1. In the browser window (either Modeling View or Assembly View), expand ORIGIN and right click on CENTER POINT to make it visible 2. Click GRIP SNAP on the Assemble tab of the ribbon 3. Click the model’s reference point 4. Choose FREE DRAG 5. Click the origin center point (no offset)
Delete Face When two solids are functioning as one, but are no longer physically connected, the delete face command can split them apart (so that the unused solid can be deleted). 1. Click DELETE FACE on the 3D Model tab of the ribbon 2. Choose SELECT LUMP OR VOID 3. Select the solid to be deleted
Weight & Center of Gravity iProperties iProperties can be used to find the centroid (i.e. center of gravity) of regions/solids (i.e. hull plates). The location of the origin and orientation of the UCS in relation to the reference point are critical for this command. In an assembly file: 1. In the browser window (either Modeling View or Assembly View), right click on solid bodies (expansion of trees may be necessary) and choose PROPERTIES/iPROPERTIES 2. Click the PHYSICAL tab of the resulting popup window (click update if needed) The resulting popup window will display the centroid’s distance away from the origin of the entire assembly.
Displacement & Draft The immersed section of the hull can be constructed by forming a prism (with dimensions equal to the boat’s length, beam, and depth) around the boat and subtracting the hull plates from the prism (then delete the disconnected solids with the delete face command). This results in a mold of the boat as if filled to the brim with concrete. The boat is then split at the draft.
Plane Commands Plane commands can be used to make waterplanes/stations/buttock planes. 1. Click PLANE drop down on the 3D Model tab of the ribbon 2. Choose OFFSET FROM PLANE to dictate the distance from the starting planes
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
Split The split command can be used to cut a solid into pieces. 1. Click SPLIT on the 3D Model tab of the ribbon 2. Choose TRIM SOLID or SPLIT SOLID 3. Select the splitting plane 4. Select the solid
Area The area command can be used to quantify areas. 1. Click AREA on the Inspect tab of the ribbon (alternatively right clicking in the model works as well) 2. Select the area
Volume The volume command can be used to quantify volumes (i.e. volumetric displacement when the hull is sliced at the desired draft). 1. In the browser window (either Modeling View or Assembly View), right click on solid bodies (expansion of trees may be necessary) and choose PROPERTIES/iPROPERTIES 2. Click the PHYSICAL tab of the resulting popup window (click update if needed)
Buoyancy For the center of buoyancy, the iProperties command can be used on the immersed section of the hull that was used to find the volumetric displacement since the center of buoyancy is the centroid of the immersed section. For the longitudinal center of flotation, the iProperties command can be used on the design waterplane area since the longitudinal center of flotation is the centroid of that area.
Stability The region properties command can be used on the design waterplane area to find the moments of inertia. In sketch mode: 1. Click REGION PROPERTIES on the Inspect tab of the ribbon (alternatively right clicking in the sketch works as well) 2. Select the region 3. Click calculate As long as the waterplane is symmetrical, the AREA MOMENTS OF INERTIA WITH RESPECT TO PRINCIPAL AXES values are needed. In accordance with the Guidelines, X is needed for the transverse moment of inertia and Y (parallel axis theorem permitting) is needed for the longitudinal moment of inertia. The sketch can also be moved (i.e. origin located at centroid) so that the INERTIA TENSOR values give the correct moments of inertia.
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CAD Techniques for Boat Design Competition
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
TABLE OF CONTENTS AutoCAD ........................................................................................................................................ 3 Building the Boat ........................................................................................................................ 3 UCS (User Coordinate System) .............................................................................................. 4 Polyline Edit ........................................................................................................................... 4 Region ..................................................................................................................................... 4 Extrude .................................................................................................................................... 5 Shell ........................................................................................................................................ 5 Subtract ................................................................................................................................... 5 Intersect ................................................................................................................................... 5 Separate ................................................................................................................................... 5 Union ...................................................................................................................................... 5 Weight & Center of Gravity ....................................................................................................... 6 Mass Properties ....................................................................................................................... 6 Displacement & Draft ................................................................................................................. 6 Divide...................................................................................................................................... 6 Slice ........................................................................................................................................ 6 Face/Edge Commands ............................................................................................................ 6 Section .................................................................................................................................... 7 Area ......................................................................................................................................... 7 Volume.................................................................................................................................... 7 Buoyancy .................................................................................................................................... 7 Stability ....................................................................................................................................... 7 Inventor ........................................................................................................................................... 8 Building the Boat ........................................................................................................................ 8 UCS (User Coordinate System) .............................................................................................. 8 ViewCube ............................................................................................................................... 9 Extrude .................................................................................................................................... 9 Shell ........................................................................................................................................ 9 Combine .................................................................................................................................. 9 Move Component ................................................................................................................. 10 Delete Face ........................................................................................................................... 10 Weight & Center of Gravity ..................................................................................................... 10 iProperties ............................................................................................................................. 10 Displacement & Draft ............................................................................................................... 10 Plane Commands .................................................................................................................. 10 Split ....................................................................................................................................... 11 Area ....................................................................................................................................... 11 Volume.................................................................................................................................. 11 Buoyancy .................................................................................................................................. 11 Stability ..................................................................................................................................... 11
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
AUTOCAD AutoCAD is 2D, and for the purposes of the Boat Design Competition, capable 3D, drafting software available for free student download from Autodesk. AutoCAD is widely used, and therefore help is readily available. Any additional questions may be sent to the Team Mentor. While many methods exist to provide the same result, a selection of recommended AutoCAD commands has been given. This guide is not intended to teach students AutoCAD.
Building the Boat When creating steel plates, do not union them together! Each plate needs to be entered as a separate line on the Weight tab of the Calculations Spreadsheet, so a separate center of gravity will be needed for each plate. It may be beneficial to build two versions of the boat; one completely solid (like the ship in the Illustrated Glossary) and one of the final product (with 1/8 inch thick hull plates). Either can be built first. Of course, each model can be copied several times for tinkering since some commands may alter the model.
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
UCS (User Coordinate System)
The UCS is the Cartesian coordinate system that dictates how things are drawn. 2D geometry is always drawn on the XY plane. The other two planes are used to modify 3D components. Rotate It may be necessary to rotate the UCS to reorient the XY plane. 1. Type UCS in the command line 2. Type the axis (X, Y, or Z) to be rotated about 3. Type the angle of rotation around that axis Origin It may be necessary to move the UCS (e.g. the boat was not originally constructed at the reference point). 1. Type UCS in the command line 2. Type O 3. Click the location of the new origin
Polyline Edit The polyline edit command can be used to transform a series of (closed) lines into a (closed) polyline. The 2D polyline can then be used to make 3D solids. 1. Type PEDIT in the command line 2. Select one of the lines 3. Type Y, then J 4. Select the remaining lines that are to be joined together
Region The region command can be used to transform a series of (closed) lines into a region. The region can then be used to make 3D solids. 1. Type REGION in the command line 2. Select all lines that are to make up the region
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
Extrude The extrude command can be used to give thickness to 2D polylines/regions. 1. Type EXTRUDE in the command line 2. Select the polyline or region to be extruded 3. Specify height of extrusion (or direction, path, taper angle)
Shell The shell command can be used to transform a solid into plates of discrete thickness. 1. Type SOLIDEDIT in the command line 2. Type BODY and then SHELL 3. Select the solid 4. Select the faces that are not to be offset 5. Specify the shell offset distance (1/8 for steel plate)
Subtract The subtract command can be used to remove one solid from another. 1. Type SUBTRACT in the command line 2. Select the first solid 3. Select the second solid
Intersect The intersect command can be used to create a solid from two overlapping solids. Similarly, the INTERFERE command retains the two overlapping solids as well as the new solid (uncheck the box in the INTERFERENCE CHECKING popup window). 1. Type INTERSECT in the command line 2. Select the overlapping solids
Separate When two solids are functioning as one, but are no longer physically connected, the separate command can split them apart (so that the unused solid can be deleted). 1. Type SOLIDEDIT in the command line 2. Type BODY and then SEPARATE 3. Select the solid
Union The union command can be used to combine solids. 1. Type UNION in the command line 2. Select all solids that are to be joined together
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
Weight & Center of Gravity Mass Properties Mass properties can be used to find the centroid (i.e. center of gravity) of regions/solids (i.e. hull plates). The location and orientation of the UCS in relation to the reference point is critical for this command. 1. Type MASSPROP in the command line 2. Select the object The resulting popup window will display the centroid’s distance away from the current location of the UCS.
Displacement & Draft The immersed section of the hull can be constructed by forming a prism (with dimensions equal to the boat’s length, beam, and depth) around the boat and subtracting the hull plates from the prism (then separate the disconnected solids). This results in a mold of the boat as if filled to the brim with concrete. The boat is then sliced at the draft.
Divide The divide command can be used to determine the spacing between an odd number of stations/waterplanes. Draw a line from the bow to the stern or from the keel to the design waterline (use PTYPE to change the nodes to a more visible symbol). 1. Type DIVIDE in the command line 2. Select the line 3. Specify the (even) number of division segments
Slice The slice command can be used to cut a solid into pieces. The orientation of the UCS is critical for this command. 1. Type SLICE in the command line 2. Select the solid 3. Type the plane (or define one) that will be used for slicing 4. Click a point on the plane where the slice is to be made 5. Select the side of the solid that is to be retained or press enter to retain both sides
Face/Edge Commands Face/Edge commands can be used to copy faces/edges of solids. 1. Type SOLIDEDIT in the command line 2. Type FACE/Edge and then COPY 3. Select the face/edge to be copied
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
Section The section command can be used to extract a region from a solid. The resulting section is a region. 1. Type SECTION in the command line 2. Select the solid 3. Type the plane (or define one) that will be used for sectioning 4. Click a point on the plane where the section is to be made
Area The area command can be used to quantify areas. If the command is used on a solid, the entire surface area will be calculated. Likewise, if the command is used on a region/plane/face/surface, the area of “one” side will be calculated. Alternatively, the MASSPROP command can be used. 1. Type MEASUREGEOM in the command line 2. Type AREA 3. Select object or specify area by clicking corners
Volume The volume command can be used to quantify volumes (i.e. volumetric displacement when the hull is sliced at the desired draft). Alternatively, the MASSPROP command can be used. 1. Type MEASUREGEOM in the command line 2. Type VOLUME 3. Select solid
Buoyancy For the center of buoyancy, the mass properties command can be used on the immersed section of the hull that was used to find the volumetric displacement since the center of buoyancy is the centroid of the immersed section. For the longitudinal center of flotation, the mass properties command can be used on the design waterplane area since the longitudinal center of flotation is the centroid of that area.
Stability The mass properties command can be used on the design waterplane area (region) to find the moments of inertia. If the “area” is not two dimensional, the mass moments of inertia display. The area must be located on the XY plane. In accordance with the Guidelines, X is needed for the transverse moment of inertia and Y (parallel axis theorem permitting) is needed for the longitudinal moment of inertia. If the area is symmetrical, the PRINCIPAL MOMENTS can be used without relocating the UCS.
7
THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
INVENTOR Inventor is 3D drafting software available for free student download from Autodesk. Inventor is widely used, and therefore help is readily available. Any additional questions may be sent to the Team Mentor. While many methods exist to provide the same result, a selection of recommended Inventor commands has been given. This guide is not intended to teach students Inventor.
Building the Boat When creating steel plates, do not union them together! Each plate needs to be entered as a separate line on the Weight tab of the Calculations Spreadsheet, so a separate center of gravity will be needed for each plate. Instead of letting the 3D MODEL commands default to JOIN, choose NEW SOLID instead. It may be beneficial to build two versions of the boat; one completely solid (like the ship in the Illustrated Glossary) and one of the final product (with 1/8 inch thick hull plates). Either can be built first. Of course, each model can be copied several times for tinkering since some commands may alter the model.
UCS (User Coordinate System)
The UCS is the Cartesian coordinate system that dictates how things are drawn. 2D geometry is drawn on the XY, YZ, and XZ planes. 8
THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
ViewCube
Reorient the ViewCube so that construction can be in accordance with the reference point (ignore that the boat’s port side will be RIGHT on the ViewCube). 1. Orbit the drawing so that UCS is displayed as shown above 2. Click the corner of the ViewCube that is presently highlighted 3. Hover over the ViewCube and right click on the HOME symbol 4. Select SET CURRENT VIEW AS HOME FIT TO VIEW 5. Select the YZ plane of the ViewCube (LEFT) 6. Hover over the ViewCube and right click on the HOME symbol 7. Select SET CURRENT VIEW AS FRONT
Extrude The extrude command can be used to give thickness to 2D sketches. 1. Click EXTRUDE on the 3D Model tab of the ribbon 2. Select the sketch to be extruded 3. Specify height of extrusion (or direction, taper angle) and NEW SOLID
Shell The shell command can be used to transform a solid into plates of discrete thickness. 1. Click SHELL on the 3D Model tab of the ribbon 2. Select the faces that are not to be offset 3. Specify the shell thickness (1/8 for steel plate)
Combine The combine command can be used to subtract one solid from another, union two solids, or create a solid from the intersection of two solids. 1. Click COMBINE on the 3D Model tab of the ribbon 2. Select either JOIN, CUT, or INTERSECT 3. Select the two solids in order of operation
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
Move Component Unlike AutoCAD, the global/world UCS cannot be moved. Instead, the model’s reference point must be moved to the assembly’s origin in accordance with the Guidelines. In an assembly file: 1. In the browser window (either Modeling View or Assembly View), expand ORIGIN and right click on CENTER POINT to make it visible 2. Click GRIP SNAP on the Assemble tab of the ribbon 3. Click the model’s reference point 4. Choose FREE DRAG 5. Click the origin center point (no offset)
Delete Face When two solids are functioning as one, but are no longer physically connected, the delete face command can split them apart (so that the unused solid can be deleted). 1. Click DELETE FACE on the 3D Model tab of the ribbon 2. Choose SELECT LUMP OR VOID 3. Select the solid to be deleted
Weight & Center of Gravity iProperties iProperties can be used to find the centroid (i.e. center of gravity) of regions/solids (i.e. hull plates). The location of the origin and orientation of the UCS in relation to the reference point are critical for this command. In an assembly file: 1. In the browser window (either Modeling View or Assembly View), right click on solid bodies (expansion of trees may be necessary) and choose PROPERTIES/iPROPERTIES 2. Click the PHYSICAL tab of the resulting popup window (click update if needed) The resulting popup window will display the centroid’s distance away from the origin of the entire assembly.
Displacement & Draft The immersed section of the hull can be constructed by forming a prism (with dimensions equal to the boat’s length, beam, and depth) around the boat and subtracting the hull plates from the prism (then delete the disconnected solids with the delete face command). This results in a mold of the boat as if filled to the brim with concrete. The boat is then split at the draft.
Plane Commands Plane commands can be used to make waterplanes/stations/buttock planes. 1. Click PLANE drop down on the 3D Model tab of the ribbon 2. Choose OFFSET FROM PLANE to dictate the distance from the starting planes
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THE APPRENTICE SCHOOL STUDENT SECTION OF THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS
Split The split command can be used to cut a solid into pieces. 1. Click SPLIT on the 3D Model tab of the ribbon 2. Choose TRIM SOLID or SPLIT SOLID 3. Select the splitting plane 4. Select the solid
Area The area command can be used to quantify areas. 1. Click AREA on the Inspect tab of the ribbon (alternatively right clicking in the model works as well) 2. Select the area
Volume The volume command can be used to quantify volumes (i.e. volumetric displacement when the hull is sliced at the desired draft). 1. In the browser window (either Modeling View or Assembly View), right click on solid bodies (expansion of trees may be necessary) and choose PROPERTIES/iPROPERTIES 2. Click the PHYSICAL tab of the resulting popup window (click update if needed)
Buoyancy For the center of buoyancy, the iProperties command can be used on the immersed section of the hull that was used to find the volumetric displacement since the center of buoyancy is the centroid of the immersed section. For the longitudinal center of flotation, the iProperties command can be used on the design waterplane area since the longitudinal center of flotation is the centroid of that area.
Stability The region properties command can be used on the design waterplane area to find the moments of inertia. In sketch mode: 1. Click REGION PROPERTIES on the Inspect tab of the ribbon (alternatively right clicking in the sketch works as well) 2. Select the region 3. Click calculate As long as the waterplane is symmetrical, the AREA MOMENTS OF INERTIA WITH RESPECT TO PRINCIPAL AXES values are needed. In accordance with the Guidelines, X is needed for the transverse moment of inertia and Y (parallel axis theorem permitting) is needed for the longitudinal moment of inertia. The sketch can also be moved (i.e. origin located at centroid) so that the INERTIA TENSOR values give the correct moments of inertia.
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