User manual · Chapter 5 of 9

3D models

Bringing in an STL model, turning it face up, sizing it, deciding how deep it sits in the stock, and slicing a model too tall to cut in one piece.

How Carvect Pro carves a model

A 3-axis machine can only reach a surface from above. So Carvect Pro treats a 3D model as a surface seen from the top: at each point, the highest part of the model is what gets cut, and anything underneath an overhang is left solid. Choosing which face points up is therefore the first decision, and the most important one.

The 3D toolpaths (see the Toolpaths chapter) then rough the bulk away and finish the surface. The fineness of the grid the model is sampled on is the Modeling Resolution in Job Setup.

Importing a model

Set up the job first, with the real thickness of the stock you will carve.
Choose Design ▸ 3D Model ▸ Import 3D Model (STL)… (it is also on both Import cards and in the File menu) and pick an .stl file.
The Transform tab opens on the right and the model appears in the 3D view, live, as you change the settings. Nothing is added to the job yet.
Set it up as described below, then press Position & Import.

A very dense mesh is simplified as it comes in, to about the precision the machine can cut, and the status bar says so. A model clicked in a project's file list is imported the same way.

Face up, rotation, size and position

The Transform tab has these settings:

Face up: Which face of the model points at the cutter: Top (as modelled), Bottom (flip over), or the Front, Back, Left or Right face. Choose the one that shows the detail you want to carve.
Rotate X, Y, Z: Fine rotation about each axis, in degrees. Rotate Z presets turn it in quarter turns on the bed.
Scale X, Y, Z: Scale factors. With Uniform ticked the three stay locked together.
Size X, Y, Z: The same thing expressed as finished dimensions. Type the size you want and the scale follows.
Position X, Y, Z: Where the model sits on the stock.

In the 3D view the model also has a handle you can drag to move it.

To come back to these settings after importing, select the model and choose 3D Model ▸ 3D Model Orientation…, which reopens the Transform tab for it. Its Orientation & Size settings also appear in Properties when the model is selected. Remember that Scale in 2D only changes X and Y: use the model's own size fields to scale all three axes together.

Model position and the Z plane

A model rarely has exactly the height of the stock. 3D Model ▸ Model Position & Z-Plane… sets how the two fit together. It shows five numbers, and the three distances always add up to the stock thickness:

Stock thickness: From Job Setup, shown for reference.
Model height: How tall the model is once scaled. Changing it scales the height only and leaves the footprint as it is. This is the depth of relief you will carve, so it affects carving time more than anything else here.
Gap (model top → stock top): Material left above the model's highest point. A small gap gives the finishing pass somewhere to start and hides a board that is not quite flat. Zero puts the model's peak at the surface.
Carve height (plane → model top): How much of the model is above the Z plane. Only this part is carved.
Floor (stock bottom → Z plane): Material left below the plane, which comes out as a flat floor.

If the model is deeper than the stock, raise the Z plane. The lowest part of the model is cut off and the rest keeps its detail. When the model is still deeper than the machine can reach, the 3D toolpath forms warn you.

The Properties tab shows the result as a sentence ("Carving 12.5 of the model", "The bottom 3 is left as the floor"), which is a quick check that the numbers mean what you think.

Reducing a mesh

A model with a million triangles slows every calculation and the preview, and most carvings do not need that much. Select the model and choose 3D Model ▸ Reduce Mesh…. You are told how many triangles it has and asked what percentage to keep. A quarter is a sensible first try. Recalculate any 3D toolpaths afterwards.

Slicing a tall model

Some models are too tall to carve in one piece: taller than the machine's Z travel, longer than the cutter's flutes, or thicker than any board you can buy. 3D Model ▸ Slice Model… cuts the model into horizontal layers. Each layer is carved from its own board and the boards are glued back into the whole.

Slice thickness: The thickness of each slice, set to the boards you actually have. The model's height rarely divides evenly, so one slice comes out thinner.
Measure from the top: On, slices are measured down from the top and the odd thin slice is at the bottom. Off, it is at the top. Put it where the model has least detail.
Number of equal slices: The other way to divide it: say how many slices and the thickness is worked out.
Slice heights: Every slice, bottom first. Select one to move its top, add a cut, or delete one to merge two. You can drag a cutting plane in the section view, or double-click to add one. Use this to keep a glue line from running through a fine detail.
Boundary vector round each slice: Draws the outline of the material in each slice on that slice's sheet. Profile around it to free the layer.
Skin under each slice: Extra thickness added to each board (1 mm to start with). Profile the boundary to the slice's own thickness and the skin holds the layer in place while it is cut, with no tabs to leave stubs on the glue face. Plane or sand the skin off afterwards and the glue face is true.
Where the slices go: A sheet each gives every slice its own sheet with its own stock thickness, which is the usual choice. Alternatively they can be laid out side by side on the current sheet.

The form warns you when a slice is thicker than the active machine can cut, and lets you carry on in case the job is meant for a different machine.

The original model stays in the job on a sheet called "Source model", so a job cut into three slices has four sheets. Keep it as a reference or delete it. Nothing registers the slices for you when gluing, so glue from the bottom up and line each layer up on its outline.

Reliefs from the Profiles library

The Profiles tab includes a library of 3D reliefs (domes, petals, mouldings and more) that need no STL file. Drag one onto the drawing, or double-click it. It lands on the "3D Profiles" layer. Select it to change its position, its size and how far it stands proud in the Transform settings, then cut it with the 3D toolpaths like any other model.

Looking at a model in 3D

Switch to the 3D tab. Orbit with the left mouse button, pan with the middle button (or Shift and the right button), roll with the right button and zoom with the wheel. The navigation cube in the corner turns the view to a face with one click, and Iso gives a three-quarter view. View ▸ Show 3D Models hides and shows the models, which helps when you want to look at the toolpaths on their own.