Subdivision Surfaces

Realsoft 3D's Subdivision Surface implementation is based on Catmull-Clark surfaces. However, Realsoft 3D supports rational SDS surfaces - there can be a 'weight' parameter associated with each control point. Increasing the weight pulls the corresponding surface point towards the control point in question.

A subdivision surface object is defined by a set of control points and a set of faces. Each face can refer to three or more control points.

There are many pointwise attributes that can be defined, such as color, illumination, or transparency. Also, there can be pointwise values for any user defined channel.

Vertex sharpness can be set for any set of vertices. It can be Rounded (default), Semi Sharp or Sharp. There's also a similar control for edge sharpness. Additionally, a 'Free' edge sharpness rounding can be defined numerically.

SDS objects can include multiple UV channels defining how textures are applied on the surface.

Realsoft 3D's SDS implementation also supports per face materials: a material name and a set of UV parameter values (one per vertex in the face) can be attached to any face.

SDS Properties

SDS supports a small but very powerful set of handles through which most commonly needed tools can be applied.

There are three sets of handles: point, edge and face handles, which can all be selected. When a handle is selected, it typically shows a set of sub handles. For example, when a face handle is selected, also the face normal handle is shown for the selected face.

The usual selection modifiers and the drag box selector are available when selecting SDS handles.

Point Handles

The point handles are shown when the SDS object is in the point editing mode.

Each SDS point acts as a translation handle by default.

Points can be duplicated by dragging them with the Ctrl key pressed.

The weight parameter associated with the points can be changed by dragging the point with the Alt key pressed.

The 'Move on normal' tool can be activated by dragging the surface normal handle.

The Bevel tool can be activated by dragging the end point of the surface normal handle.

Handles shown in the point editing mode

Edge Handles

The edge handles are shown when the SDS object is in the edge editing mode.

Handles shown in the edge editing mode

Face Handles

The face handles are shown when the SDS object is in the face editing mode.

Handles shown in the face editing mode

Property Gadget

The SDS property gadget has the following frames: SelectedPoints, SelectedEdges,Rendering, MultiUV, Faces.

Selected Points frame
  • Points - the number of vertices in the SDS object

  • Selected - index of the selected vertex. If more than one vertex is selected the index of the first selected vertex is shown in the conflict color.

  • Position - 3D position of the selected vertex.

Selected Edges frame

Rendering Frame

Multi UV frame
  • Channel - possible UV channels.

  • Add - add the selected channel as a UV channel.

  • Del - Delete the selected UV channel. The selection is shown in the list view gadget.

  • Add Default - adds the default UV channel (UV coords).

  • List of UV Channels added to the object.

Faces frame
  • Faces - number of faces in the SDS object.

  • Selected Face - index of the selected face. If more than one face is selected the index of the first selected face is shown in the conflict color.

  • Selected faces only - if checked the Material list view below shows only those face materials and face textures that are attached to the selected faces. Otherwise all face materials and face textures are listed.

Additional Controls in The Wire Tab