Retopo

Snap Distance

Specifies the minimum distance, in pixels, between subdivision vertices and the surface of the reference before triggering the snap of CVs to the surface. You can specify values between 1 and 10 where at higher values, CVs are more likely to get snapped.

Edge Flow

When on, the inserted edge or edge loop adjusts to best fit the curvature of the neighboring edges to maintain the shape of the subdivision body. Edge Flow works when inserting perpendicular and parallel edges.

Relaxation Strength

Sets the speed at which Relax (Hotkey: RMB + drag) gets applied to subdivision surfaces. Use higher values if you want Relax applied quickly to regions of the surface. Use lower values to apply Relax at a slower rate, which give you better control over the amount and to which areas the effect gets applied.

Relax evens out the spacing between vertices on the subdivision surface. This results in more uniform topology especially in places where acute and obtuse angles appear between subdivision edges.

Create History

Turn this on to preserve the linking between the subdivision CVs and the reference mesh or object if you leave the tool.

Persistent Projection

Turn this on if you want to preserve the CV linking between the subdivision CVs and the reference mesh when you use another tool to modify the subdivision surface.

Note that if you move CVs using the Transform tool, and then return the Retopoolgy Tool, the CVs you moved will snap back to their original position when modified in the Retopo tool again.

Show Hotkey Help

Toggles the hotkey help overlay image on and off.

Use the Retopo tool with a reference object, such as an Alias NURBS or triangulated meshes imported from other applications object to:

• Create subdivision topology based on the shape of a reference object.
• Reshape an existing subdivision body based on a reference object.
• Add topology to an existing subdivision body when set to a reference object.

Create new topology based on the shape of a reference mesh or NURBS surface

1. Shift-select the tool to open the control window.

   

   The reference object is now set to the Retopo tool so that now the topology you create now snaps to the reference object.

   Note: Preselecting a reference object before accessing the tool also sets it to the tool.

2. Click anywhere on the reference mesh or object.

   A green dot appears and snaps the surface of the reference mesh. These dots become the vertices that create the framework for your subdivision faces.

   Tip: You can move a dot by dragging it or delete it by pressing Ctrl + click after you have dropped it on the reference object.

3. Continue to drop dots until you are ready create faces between them. To do this, move the cursor over the dots while holding Shift. The tool enters face preview mode highlighting the possible faces.

4. Shift-click a preview face to create it.

   

5. Continue dropping dots to build new faces or extend existing edges and edge loops (see Extend subdivision edges and edge loops below) to build more tolopology.

   Tip: The best way to generate topology, is to drop a few dots in a small area at a time rather that dropping a number of them over the entire reference surface. After creating some faces, you can extend the edges to build out the topology.

6. Begin shaping the new topology by dragging CVs and edges or MMB dragging edge loops.

   

7. Refine the surface by adding edges and edge loops, or relaxing vertices.

   See Refine subdivision surfaces using the Retopo tool.

Extend subdivision edges and edge loops

To use Extend edge and Extend Loop to build subdivision geometry, your subdivision body must be linked or projected to a reference object.

1. Move the cursor over the edge or edge loop while holding Shift.

   The tool enters preview mode highlighting the edge and edge loop that will be extended.

2. Do one of the following:

   • To extend an edge, Shift + drag the preview to position the extended edge, then release.

   • To extend an edge loop Shift + MMB drag the preview to position the edge loop extend, then release.

     

Shape subdivision objects to a reference object

You can snap an existing subdivision surface to a reference mesh or NURBS object, and then shape the subdivision body using the reference object as a guide.

1. Select the tool.

2. In the viewport, pick the reference object, and then click Next.

3. Pick the subdivision body you want to reshape, and then click Go.

   

   With the subdivision model now projected onto the reference object, the CVs snap to the reference surface.

   Note: If the subdivision CVs are not snapping to the reference object as expected, try adjusting the Snapping Distance in the Retopo tool options.

4. Begin reshaping your subdivision body to fit the form of the reference object by dragging CVs and edges or MMB dragging edge loops.

   

The Retopo tool provides several features for refining subdivision surfaces, such as adding edges and edge loops, relaxing CVs to generate more uniform topology, deleting components, and more.

Edit a subdivision body using Retopo tool

If you created or previously modified your subdivision body using the Retopo tool and have not exited the tool, skip this section.

1. Select the Retopo tool .

2. In the viewport, click Next.

3. Pick the subdivision body you want to modify, and then click Go.

   You can now use the tool to modify your subdivision body.

   Note: You can also preselect the subdivision body before accessing the tool.

Insert edges and edge loops

1. Move the cursor over the subdivision surface while holding Shift.

   The tool's preview mode highlights the new edge.

2. Position the edge preview and click to add it to the subdivision body.

   

Relax vertices

Use Relax to even out the spacing between vertices on the surface resulting in more uniform topology. You can control the intensity of the relax effect by adjusting the Relax Strength option in the Retopo tool options.

• Apply Relax by moving the cursor over the surface while pressing the RMB.

Cut edges

Use the cut tool to interactively split and rebuild edges, and insert CVs.

1. Move the cursor over an edge or CV while holding Ctrl + Alt.

   A green dot appears snapped to the edge or CV.

2. Do one the following:

   • To cut an edge at a point along its length, position the dot at start of the cut and click.
   • To cut from the location of a selected CV, click.
   • In either case, a red line displays with its end at the cursor. This indicates the path of the cut.

3. Move your cursor to direct the line to position of the cut end, and the click.

Delete components

1. Move the cursor over the component you want to delete while holding Ctrl. The tool preview highlights the components that can be deleted in red.
2. Click a highlighted component to delete it.