Why am I getting a "Collisions Limit Exceeded" error when using Pyro in Cinema 4D?

“Collisions Limit Exceeded” error

This error most often occurs when simulations run on a GPU that has limited available memory (for example, integrated graphics) and the collision budget is exceeded.

Why this happens

Cinema 4D’s newer simulation tools use the GPU by default (set in Project Settings). On systems with integrated GPUs or low‑VRAM cards, memory pressure during simulation can trigger the error.

Workaround

Switch the simulation device to the CPU so the solver can use system RAM. If your machine has a discrete GPU with more VRAM, you can also select that device instead.

Steps

1. Open Project Settings > Simulation > Scene.
2. Set Device to CPU (or choose a discrete GPU with sufficient VRAM).
   From Menu: Project Settings (Ctrl+D) > Simulation > Scene with Device set to CPU
3. Re‑run the simulation.

Notes

• CPU simulations may process more slowly, but playback should be smooth once cached.
• Integrated graphics are GPUs built into the CPU and share system RAM (for example, Intel HD/UHD/Iris, AMD Radeon Vega APUs). Dedicated GPUs have their own VRAM and are preferred for simulations.