Direct Modeling Operations

This section describes direct modeling operations offered by BricsCAD. These operations are accessible via the Quad tool.

Alternatively, you can use Direct Modeling Menu or Direct Modeling and Deform toolbars:

The Align UCS tool () launches the UCS command with the Face option selected.

If the UCSDETECT system variable is ON, the UCS aligns to a face automatically. The UCS-icon changes respectively. Hit the TAB key to select an obscured face. Click the DUCS field in the Status Bar to toggle the dynamic UCS feature on and off.

The following direct modeling operations are available in BricsCAD:

Icon	Command	Applies to	Description
	dmPushPull	Any face of a 3D solid or surface.	Adds volume to or removes volume from a solid via cursor movement or direct distance input.
	dmMove	Cylindrical, spherical, conical, and toroidal faces of a 3D solid or surface. Linear and circular edges of a 3D solid or surface. Whole 3D solids, surfaces, and other entities.	Moves the selected geometry with a vector in the XY- plane of the current UCS. When the face or edge of a solid or surface is moved, adjacent faces and edges are adjusted to preserve the correct solid/surface topology.
	dmRotate	Planar, cylindrical, spherical, conical, and toroidal faces of a 3D solid or surface. Whole 3D solids, surfaces, and other entities.	Rotates the selected geometry around an axis. When the face of a solid or surface is rotated, adjacent faces and edges are adjusted to preserve the correct solid/surface topology.
	dmSimplify	3D solids, surfaces, and their faces.	Simplifies the geometry and topology of entities and subentities.
	dmStitch	Surfaces	Stitches disjoint surfaces into a single 3D solid or a single surface.
	dmAudit	3D solids and surfaces	Checks and fixes geometrical and topological errors in ACIS solids and surfaces.
	UCS	Planar faces of 3D solids and surfaces.	Aligns the UCS to a face.
	dmExtrude	Closed 2D entities and detected closed boundaries.*	Extrudes 2D entities or boundary to create solids.
		Planar faces of 3D solids and surfaces.	Adds volume to or removes volume from a solid. (Optional): Create the new volume as a separate solid.
		Closed 2D entities and detected closed boundaries on a planar face of a solid.	Extrudes 2D entities or boundaries to create solids or surfaces. (Optional): Create the new volume as a separate solid.
	dmRevolve	Closed 2D entities and detected closed boundaries.*	Revolves a 2D entity on an axis to create a solid or a surface.
		Planar faces of solids and surfaces.	Adds volume to or removes volume from a solid. (Optional): Create the new volume as a separate solid.
		Closed 2D entities and detected closed boundaries on the planar face of a solid.	Revolves a 2D entity on an axis to create a solid or a surface. (Optional): Create the new volume as a separate solid.
	xFaces	Surfaces and faces of 3D solids.	Extracts a set of 3D solids or surface faces as a new, 3D surface object.
	dmCopyFaces	A set of 3D solid faces.	Copies a feature (protrusion or depression), from one 3D solid to another Or copies it to a different location on the same 3D solid.
	dmThicken	Faces of 3D solids and surfaces.	Thickens faces to create 3D solids.
		Surfaces	Thickens surfaces to create 3D solids.
		Wire entities; lines, polylines, circles, ellipses, arcs, helices, and splines.	Sweeps a circle along a wire to create a new 3D solid.
	dmFillet	Sharp edges of a 3D solid or surface.	Creates a fillet between adjacent faces that share a sharp edge(s).
	dmChamfer	Sharp edges of a 3D solid or surface	Creates a chamfer between adjacent faces the share a sharp edge(s).
	Erase	Faces of a solid or a surface. Whole 3D solids and surfaces.	Deletes entities. When the faces of a solid entity are deleted, the adjacent faces are extended to fill any gaps. When the faces of a surface entity are deleted, the gap is filled only if the faces form a fillet.
		Free edges of a surface (a surface edge is called "free" if it has only one adjacent face)	If the free edge(s) belongs to one or more holes in the surface, the hole(s) are deleted and the gap is filled automatically.
		Edges between coplanar faces.	Deletes the edges, between coplanar faces, to unify the faces.
	dmExtrude	3D curves and edges of 3D solids and surfaces.	Extrudes curves and edges in a particular direction to create surfaces. This is defined automatically but can also be set by the user.
	dmRevolve	3D curves and edges of 3D solids and surfaces.	Revolves curves and edges around the selected axis to creates surfaces.
	dmDeformPoint	Faces of a 3D solid or a surface.	Deforms the selected set of faces at a point.
	dmDeformMove	Edges of a 3D solid or a surface.	Moves and rotates edges to deform faces.
	dmDeformCurve	Edges of a 3D solid or a surface.	Changes the geometry of edges to deform a face.
	dmTwist	3D solids, surfaces or regions.	Twists a portion of an object around an axis.
	dmUpdate	Drawing	Updates 3D.
	dmSelect	Edges and faces of 3D solids and surfaces	Selects the edges and faces of 3D solids or surfaces based on their geometric and topologic properties, i.e. selects faces of a smooth side of a given solid or selects a set of faces that form a protrusion or depression feature.

*If the Select detected boundaries option of the SELECTIONMODES system variable is switched ON boundaries, enclosed by 2D linear entities in the XY-plane of the current UCS, are detected automatically.

Selection Preview

When the Quad cursor menu is active, the SELECTIONPREVIEW system variable is unused unless a command prompts you to select an entity (see Selection Settings).

Select geometry

• Hit the TAB key to select obscured geometry.

• The SELECTIONMODES system variable controls which subentities highlight: edges, faces and/or detected boundaries.

• Hit the Enter key or right-click to conclude the selection procedure, if you enter a direct modeling command in the command line or selected it from a menu or toolbar.

• Click the mouse to confirm the selection of geometry to execute the command if you launch a command from the Quad cursor menu.

• Window selection: to select the faces or edges of 3D solids and surfaces, hit CTRL. An icon next to the cursor indicates what will be selected.

• The dmSelect command allows you to select edges and faces based on their geometrical and topological properties:

  • Edges of a particular length.

  • Edges that form a concave/convex network.

  • Edge loops on the border of a set of connected faces.

  • Faces of a particular area.

  • Smoothly connected faces (G1 - tangent faces, or G2 - curvature continuity).
    
    G0: No continuity (left), G1: Tangent Faces (middle) and G2: Curvature continuity (right)

  • Fillets of a radius.

  • Cylindrical protrusions of a radius.

  • Protrusion or depression features; pockets, extrusions or ribs.

The value of a particular length, area or radius can be taken from a selected edge/face.

To control dimensions

A dynamic dimension displays with the dmPushPull command.

Make sure the Quad and Dynamic Dimensions are switched ON.

1. Hover the cursor over the face you want to move.
   The face highlights.

2. Choose PushPull () from the Direct Modeling command group of the Quad cursor menu.
   The selected face moves with the cursor and a dynamic dimension field displays the relative distance.
   

3. (Option) repeatedly hit the TAB key to see the distance with respect to an internal face, parallel to the selected face (left) or the bottom face (right).
   Press and hold the SHIFT key and hit the TAB key to reverse the display order of reference faces.
   

4. Type a value in the dynamic dimension field, then hit Enter.

Make holes

Use the SUBTRACT command.

If you push-pull a closed 2D entity that lies on a face of a solid, a hole is created when you push the 2D entity through the solid.

To make a (circular) hole through a solid

1. Make sure Dynamic UCS is active.

2. Launch the Circle command.

3. Move the cursor to the face you want to create to hole on.
   The UCS automatically aligns to the face the cursor is on.

4. Draw a circle on the face of the solid.

5. Hover over the circle, then choose Extrude () from the Model command group of the Quad cursor menu.
   
   

6. Do one of the following:

   • Type a distance in the dynamic field to define the depth of the hole.
   • Push the circle through the solid to create a through-hole.

7. (option) Choose Push/Pull () from the Model command group of the Quad cursor menu to modify the radius of the hole.

8. (option) Use the dmDistance3d command to apply a distance constraint between the side faces of the solids and the center of the cylindrical surface of the hole to control the position of the hole.

9. (option) Use the dmRadius3d command to control the radius of the hole.

To make a hole in a surface

1. Create a 2D closed entity, e.g. an ellipse.
   
   

2. Hover over the 2D entity.

3. Choose Extrude () in the Model command group of the Quad cursor menu.

4. Extrude the 2D entity in the direction of the surface.
   

5. Hit the CTRL key twice to select the Subtract option of the DmExtrude command.
   
   

6. Click the mouse to create the hole.

Delete features

To delete a hole, you must delete all the internal faces and/or surfaces of the hole.

To delete a circular hole

1. Hover over the cylindrical surface of the hole.

2. Choose Delete () in the Model command group of the Quad cursor menu.

To delete a rectangular hole

1. Hover over one of the visible internal faces of the hole.
   The face highlights.

2. Choose PushPull () from the Model command group of the Quad cursor menu
   

3. Drag the selected face to close the hole.

To delete a niche or recess

1. Hover over the back (bottom) face of the recess.
   If the face is obscured in the current view, hit the TAB key until the face highlights.

2. Choose PushPull () in the Model command group of the Quad cursor menu.
   
   

3. Drag the face to close the gap.

To delete a hole in a surface

1. Hover over the edge of the opening.
   The edge highlights.

2. Choose Erase () from the Model command group of the Quad cursor menu.
   

To delete a depression (hole or pocket) or a protrusion feature (extrusion or rib)

1. Select one or more faces of the feature you want to delete.
2. Click the Protrusion ( ) or Depression () tool button in the Select panel of the Solid ribbon tab or from the Select command group of the Quad.
3. Click the Erase () tool button.
   
   

Remove edges between coplanar faces

When two or more faces are made coplanar, e.g. with the DmPushPull command, it might be necessary to remove the shared edges.

1. Select the three faces.

2. Choose Delete () from the Model command group in the Quad.
   
   
   
   The shared edges are deleted and the three selected faces are unified.
   
   

Copy a Feature

The dmCopyFaces command allows you to copy one or more features from a 3D solid (depressions - holes, grooves, and pockets - or protrusions - extrusions and ribs), to a new location on the same or a different 3D solid.

To copy a feature:

1. Select all faces of the entire feature(s) (see Select Geometry).

2. Make sure dynamic UCS is enabled.
   Note Bricsys recommends that you always enable DUCS with the Direct Modeling toolset.

3. Click the Copy Faces () tool button:

   • on the ribbon: Solid | Edit | Copy Faces .
   • on the Direct Modeling toolbar.
   • in the menu bar: Model | Direct Modeling | Copy Faces
     You are prompted: Enter base point:

4. Specify the base point.
   You are prompted: Select an insertion point or [Rotate/mUltiple/MOde]:

5. (Optional):

   • Use the Rotate option to rotate the faces around the Z axis of the UCS.
   • Use the Multiple option to insert the multiple copies of a feature.

6. Specify the insertion point. The feature is copied from the base point to the insertion point with dynamic UCS.

Deformable modeling

Use the tools on the Deform toolbar, to deform a set of adjacent faces on a 3D solid or a surface, to create complex aesthetic shapes.

The faces are always deformed if:

• The external boundary (edges, which are adjacent to only one of the selected faces) remain unchanged.

• The internal boundaries (edges, which are adjacent to two of the selected faces) is deformed together with the faces.

• The initial continuity between deformed faces (G1 – tangent faces, or G2 – curvature continuity) is kept when deformed.

For a twist deformation, it is possible to specify the continuity between the deformed and the fixed portion of the entities.

Deformation can be defined in several ways:

• Twist the whole entity or a portion.

• Move a point on a face in any direction in 3D space.

• Move or rotate one or more edges.

• Replace an edge with a given 3D curve.