PRIME MOTIONSurface modelling
A surface is a sheet with no thickness. Surfaces are a way to build a shape that a solid tool cannot make in one step, such as a seat with a compound curve, and then close it into a solid. A part is machined only from solids, so a surface design always ends with Thicken, Stitch or Boundary Fill.
Switching to Surface Modeling
Long-press the Design tab and choose Surface Modeling under DESIGN MODE. The rail changes to the surface tools; Solid Modeling switches back. The choice lasts until the app is closed, and it changes only the rail: bodies of both kinds stay in the design.
In Surface Modeling the rail has New Sketch, Create, Pattern, Stitch, Modify, Assembly, the construction families, Analyze and Insert. Primitive, Hole, Fillet, Shell, Combine and Joinery are only in Solid Modeling.
Create
Extrude, Revolve, Sweep and Loft work as they do for solids (see 3D features), but make sheets from open curves as well as closed ones. Three creators are only here:
| Tool | Picks | Value | Commit |
|---|---|---|---|
| Thicken | Surface body | Thickness (2 mm) | Thicken |
| Patch | Closed loop to fill | — | Patch |
| Ruled | Edge to extend; Type Normal, Tangent or Direction (with a Direction pick) | Distance (10 mm) | Ruled |
Boundary Fill makes a solid from the closed spaces that surfaces and bodies enclose: pick the Tool bodies / surfaces, tap Compute Cells, tap the cells to keep, and tap Create.
Stitch and edit
| Tool | What it does |
|---|---|
| Stitch | Sews two or more surfaces that share edges (Surfaces to sew (2+)) into one. Sheets that close a volume become a solid. |
| Unstitch | Splits a Solid body back into its separate faces. |
| Trim | Cuts the Surface to trim where the Cutting tool crosses it. |
| Reverse Normal | Flips which side of a sheet is its outside. One tap on the sheet; no drawer. |
| Offset Surface | Makes a copy of the tapped sheet 5 mm away. One tap; the distance is fixed. |
| Extend | Extends the tapped edge of a sheet by 10 mm. One tap; the distance is fixed. |
Modify in this mode has Offset Face, Scale, Delete and Align.