Solid primitive shapes merged by operations such as UNION, SUBTRACT, and INTERSECT commands are the basic commands to create new and complex solids or composite solid models by joining or subtracting them or finding their intersecting (overlapping) volume.  Modeling tools range from entering precise measurements or by changing values in the Properties palette, to more freeform shaping methods such as grip and gizmo editing.  Some methods are specific to 3D solids or meshes.  Other methods are shared.

The 3D mesh primitives can also be modified and reshaped using the Free-Form Design options.  Creases, splits, and increasing levels of smoothness can be applied and sub-objects (faces, edges, and vertices) can be dragged to deform the object.  For more modeling details, the mesh can be refined in specific areas before reshaping it.

Example Union

The UNION command joins or combines the total volume of two or more intersecting or touching solids or two or more intersecting or touching regions into a combined object.

Non-touching solids can be combined together using the UNION command. This created a group of non-touching elements that can then be moved, copied, rotated etc. together as on entity. Once grouped, the non-touching solids will be selected together when one solid is selected, indicating they are grouped.  The
GROUP command can also be used to combine non-touching solids.

The SEPARATE command on the Solid Editing toolbar provides an option that lets you separate solids that are non-touching but are combined as a group. This tool will not work on combined and touching solids. Alternatively, use the SOLIDEDIT command and then select Body then SEP for separate and then select the group to ungroup.

Figure 1 Non-touching solids can be combined into GROUPS using the UNION or GROUP command for manipulation as one unit.

To use the SOLIDEDIT command, apply the following procedure to separate two non-touching solids into individual solids:

 1.    Invoke the SOLIDEDIT command.

 Solids editing automatic checking:  SOLIDCHECK=1

2.    At the: Enter a solids editing option [Face/Edge/Body/Undo/eXit] <eXit>: select b for Body and select Enter.

3.    At the: Enter a body editing option[Imprint/separatesolids/Shell/cLean/Check/Undo/eXit] <eXit>:  select sep for separate solids

4.     At the: Select a 3D solid: Select the group

5.    At the: Enter a body editing option

[Imprint/seParate solids/Shell/cLean/Check/Undo/eXit] <eXit>: Click Enter to remove the group action.

Example Press Pull

The PRESSPULL command can be used to create openings in walls created by Polysolids, Extrusions or other 3D solid geometry.   The boundaries must be placed on the faces of these objects with the use of the UCS or the DUCS.   When the object is moved, the boundary geometry stays behind and must be erased.  

Figure 2  A bounded are alike a circle on the face of a solid box, can be “pushed” to reduce volume and create a hole or “pulled” to extrude new volume  by the PRESSPULL command.   A 2D circle area pulled up with the PRESSPULL command is simply extruded into a cylinder. 

Free Form Design

Check out the CAD Tip link to find some tips on free form design with mesh objects.

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