That happens sometimes with me: Normally the problem is the thickness of the mesh, but also sometimes is not enough resolution in Dynamesh, thats also makes the polygons get crazy as hell when the dynamesh is applied and for the last try i normally go to: Deformation> Size (and increase for the max 1 time and then click in…
Troubleshooting this involves one or many of the following: 1) Duplicate the mesh, Dynamesh the new one. 2) Increase the mesh thickness. 3) Make a tiny tiny modification to the mesh, and then dynamesh it. There may be more.
Everytime I dynamesh something I extract, I get this kind of crazy breakdown whenever I sculpt on it. Anyone know what's wrong? I found out that it happens when your sculpt is too thin, but it happens even when it has an enough amount of thickness to it too. Annoying as it is, it just really freaks me out :(
Try changing your dynamesh resolution. I ran into this issue the other day on a mesh that wasn't super thin or in any other obvious way unusual. It'd be fine to dynamesh up to a certain resolution, but then suddenly corrupt like what you're seeing there once it hit a certain, not extraordinarily high res.