In this guide, you’ll learn how to use the Intersection Solver to quickly fix problem areas where, for example, clothing intersects with a character’s skin.

We’ll work with a Heavy Shape and the Sport_Short_Color1 Deformable.

🎬 Check our Tutorial Video:

What is the Intersection Solver?

The Intersection Solver is a tool that can be associated to any Deformable (garments, accessories) to detect, visualize and solve intersections with the Template or Shape it is fitted to - meaning, you can fix an intersection of a Deformable in the Heavy shape only.

This is useful in cases where an imported asset has minor modeling issues or when the clothing doesn’t perfectly conform to the character’s shape.

How to use the Intersection Solver

Create the Intersection Solver – Right-click on the Deformable and select Create → Intersection Solver.
Detect intersections – Click Verify to detect any intersections between the Deformable and Template/ Shape.
Fix intersections – Browse the list of detected intersections and fix them individually, or apply all suggested fixes at once by clicking Fix All.
Finalize the adjustments – Either run Verify again to check for remaining intersections or save the updated Deformable by clicking Apply Changes.

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Fixing intersections between a Template and a Deformable will automatically trigger fitting updates on all the Shapes. As a result, the Deformable’s fitting will improve across all Shapes thanks to the intersection fixes on the Template!

For more information about the Intersection Solver, check the official documentation.

1. Preview Deformable intersection with Template/Shape

Start by dragging the following elements into the Outliner:

Heavy
Sport_Short_Color1

Info: Rotating the character you’ll likely notice intersection issues right away, for example, the shorts may clip through the body. Let’s fix that.

2. Create an Intersection Solver

In the project tree on the left, locate Sport_Shorts_Color1
Right-click on it
Select: Create → Intersection Solver

Info: A new object called Intersection Solver will be created as a sub-element of the Sport_Shorts_Color1 Deformable.

3. Scan for Intersections

Click the Intersection Solver to select it
In the right-hand panel, click Verify, this will scan for overlapping geometry between the Deformable and the character body

After the scan, a list of Intersection Groups will appear, each group represents a specific area detected by the system

4. Highlight Problem Areas

Enable Highlight All Groups, the Popul8 Express will visually highlight all detected collision zones
In this case, you’ll see one problematic area in the back of the character.

5. Fix All Intersections

Click Fix All, Popul8 Express will automatically apply optimal settings to resolve all detected issues.

Tip: You don’t need to adjust any settings manually, the default values work well for most cases.

6. Re-Scan for Intersections

Click Verify to re-scan and check if any additional adjustments are needed

In this case, a message will be displayed indicating that the Intersection Solver has no longer detected any intersections.

7. Apply the Fixes

Click Apply Changes to confirm the fix

In the confirmation dialog, click Yes

Info: Your changes are now saved and the intersections are resolved.

8. Review Deformable fit on Template/Shape

For peace of mind, drag the following items back into the Outliner:

Heavy
Sport_Shorts_Color1
You can also add Sport_Shirt_Color1

Your model should now look clean, the armpit issues are gone, and the Deformables have been properly conformed to the character shape. You’re ready to move on!