aflatsprite
Geometry Nodes Simulation & Non-Sim Real-Time
Softie Collision System
Have you ever wondered why you need to dive into lattices, shape keys, or—even worse—soft body simulations just for simple deformations? I thought the exact same thing, so I built an instant collision system using Geometry Nodes. It's perfect for quick deformations, like colliding spheres or a hand grabbing a soft object. Even better, self-collisions are also included so your characters will never intersect themselves again!
1.7 Update!
- UI Overhaul: All custom attributes (such as variable hardness) now live under the Custom Attributes/Masks dropdown in the modifier panel. Non-essential dropdowns are closed by default for a cleaner initial UI.
- Fixed a bug where raycast normals were still calculated for selection masks even when deformation was correctly avoided, which caused issues on surrounding geometry.
- Resolving the raycast calculation bug also improves the overall performance of the modifier.
- Adjusted main default values.
1.6 Update!
- Includes a check and an automatic fix for non-manifold SELF collisions.
- Simulation has been moved to a separate modifier to increase the performance of the main tree and has been marked "experimental".
- Default value changes and visual tweaks.
- Now variable and selection named attributes include text to help first-time users.
1.62 Patch
- Now you can mask what gets affected by the modifier. Just input your group attribute in the "Mask Group" field :)
1.61 Patch
- Added a "Show Affected" toggle in the visibility controls to highlight collided mesh parts—especially useful during sculpting workflows.
1.5 Major Update!
- Added SIMULATION collision type.
- Built upon the existing XPBD cloth dynamics solver (Requires Blender 5.2), featuring custom pin and force algorithms along with pressure, recovery controls, and dynamic masking.
- Variable hardness attribute now supports the modifier object (this object attribute supersedes the collision collection attribute).
1.4 Critical Update!
- Variable Hardness is now implemented thanks to Rob! Simply enter the name of your hardness attribute—whether it's a weight paint group or another attribute. A weight of 1 represents hard, and 0 represents soft.
- Huge performance improvements to self-collision (evaluation reduced from 60ms to 30ms on heavier meshes).
- Added meaningful tweaks and safety nets.
- Added attribute selection to improve performance.
- Implemented "Away" vector for deformation.
1. Control The Hardness
The object hardness slider lets you choose whether the collision object is soft or retains its original stiffness. At 0.5, both interacting objects act soft! Play around to find the exact interaction behavior you need.
2. Self-Collision
Now includes a self-collision option—perfect for character animations!
3. Multiple Objects
You are not limited to using only one collision object. Add and interact with as many objects as your scene requires for complex multi-body soft contact setups.
4. ... And It's Fast! ⚡
Built purely for real-time viewport responsiveness. Simple geometry setups using multiple collision objects execute in under 10ms tree calculation time (tested on i7-14700F).
1.3 Update!
- Changes to default values.
- Increased default performance.
- Minor tweaks.
1.2 Update!
- Added a new mask option: Custom Mask + Distance.
- Minor performance tweaks and improvements.
1.1 Update!
- Added option for self-collision—perfect for character animations when the mesh overlaps.
⚠️ 5. Warning! This Is Not Magic!
Without per-frame velocity and history evaluation, it is impossible to build a universal collision system that covers every scenario. Please keep the following technical parameters in mind:
- Use simple manifold objects for best visual evaluation.
- Intended for surface deformations only; extremely deep penetrations will cause raycast vectors to break.