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

Problem:

While numerous factors can contribute to the Collisions Limit Exceeded error you are receiving, the most common culprit we've identified is related to the use of *Integrated Graphics. This refers to the GPU that's built directly into the CPU. Similarly, this can also occur with GPUs that possess a limited amount of VRAM.

Our new simulation tools are primarily designed to utilize the GPU and the GPU is chosen by default in the Simulation settings. So, if your hardware lacks a sufficient amount of available memory, you might encounter a "Collisions Limit Exceeded" error.

Workaround:

Given these circumstances, you might find it beneficial to switch the simulation tools to operate using the CPU instead of the GPU. Doing so will ensure that Pyro has access to all available system memory as opposed to the small amount of RAM allocated to integrated graphics, which could help avoid these errors.

Please keep in mind, though, that while processing with the CPU might take a bit longer than using the GPU, the playback performance should remain satisfactory once the simulation is cached.

 
You can switch to CPU in the Project Settings > Simulation > Scene > Device settings:

*What is Integrated Graphics?

Integrated graphics: refers to a graphics processing unit (GPU) that is built into the same chip as the central processing unit (CPU), rather than being a separate component like a discrete or dedicated graphics card. This integration typically occurs in most laptops and many lower-end desktops.

Integrated graphics share system memory (RAM) with the CPU, unlike dedicated graphics cards which have their own dedicated video memory (VRAM). Due to this shared memory, integrated graphics aren't usually as powerful or capable as dedicated graphics cards.

However, integrated graphics are generally more power-efficient and produce less heat than a dedicated graphics card. They are typically sufficient for basic tasks such as browsing the web, watching videos, and doing office work. They can also handle lighter tasks adequately, but they may struggle with more graphically-intensive tasks such as 3D rendering or high-resolution video editing.

Notable examples of integrated graphics solutions include Intel's HD Graphics, UHD Graphics, and Iris Plus Graphics series, as well as AMD's Radeon Vega series found in their APUs (Accelerated Processing Units, which combine CPU and GPU on the same chip).