I found out last night that ZBrush uses the CPU rather than the GPU. Does anyone know if there’s be any plans to change this in future releases? It would make sense for it to use the GPU, surely…? Once multiple meshes are added together and those subdivisions increase, everything slows down.
Zbrush has always been CPU based, and while I’m not a developer and can’t speak for them, it seems unlikely that that is going to fundamentally change any time soon. Zbrush’s unique architecture is what allows it to handle unusually large polycounts even on relatively modest hardware. Most other programs are traditionally restrained by hardware limitations, but you can get impressive poly performance in Zbrush on a laptop or ten year old CPU without an industrial grade GPU.
There may be specific features that involve the GPU to a greater degree.
If you’re experiencing a “slowdown” in Zbrush, it is likely you’re trying to work outside the limitations of your system, and could benefit from some additional polycount discipline. If you can’t manage a certain polycount in Zbrush, you arent going to manage it anywhere else either, GPU or no.
If you don’t feel that is the case, please feel free to post screenshots and describe the situation in which you are experiencing the “slowdown”, and we can try to sort that out.
Hmm. Admittedly I am still new to Zbrush, so it could partially be due to a lack of polycount discipline. Though I usually keep subdivisions around 4 or 5 and use ZRemesher every so often. I don’t think it’s my PC struggling anyway. I’m running it on an SSD, with 16GB RAM, an i7 4790K. And though it doesn’t seem to matter, I have a GTX 1080 as well.
What do you mean by “slows down”, and in regard to which tools/functions in Zbrush?
Sculpting /display wise, brush performance stays remarkably good, even on meshes that would be problematic for stability/saving, and for other cpu-intensive functions in Zbrush. In other words, you’re more likely to run into general problems associated with ultra dense meshes long before Zbrush can’t actually handle that mesh in a live session for the purposes of sculpting.
Not every tool works the same way though. CPU bound operations that require Zbrush to do intensive polygon crunching will still be limited by your hardware, and by Zbrush itself. So things like Zremesher, Dynamesh, UV unwrapping, Decimation Master, etc, will all hit a performance wall far sooner than some of the crazy polycounts you can actually sculpt on.
This isn’t a problem if your mesh has multiple levels of subdivision, because you can always use a lower available level for these tools. Despite the flexibility granted by remeshing tools, Zbrush is still designed to work best on a tool with multiple subD levels. One of Zbrush’s tricks is to display a lower level of subdivision when rotating the mesh, in order to maintain good performance. If there is no lower level of subdivision, it has to display the highest which will slow performance.
You can trap yourself if you attempt to work on too dense of a mesh at a single level of resolution. Ideal classic workflow would be to use frequent remeshing, or tools that only work on a single level of subdivision, to quickly establish basic medium rez form, then create a new multi subD tool with a low poly base with ZRemesher and detail projection for fine surface detail sculpting. By that time, your need to remesh should be minimal, and in the event that you do need to, you can simply repeat that operation.
Kind of sounds like maybe you are combining subtools instead of keeping them separate? That would definitely slow down zbrush. I’d recommend not combing subtools.