I have searched the archives for a solution to my problem and am very surprised that no one has had it before. I built a mesh and an extrusion surface. There are no errors in either. I then extrude the extrusion surface. I have negative volumes and bad tets, but I know how to fix those. However, I have 599 double vertices. I know, you are probably saying, well, do a vmerg. I do, and no vertices are merged. If I change the tolerance from 0.001 to 0.01 I may merge a few vertices, but then when I check, I have increased the number of double vertices by those eliminated. I have tried doing a vplot with vertex numbers turned on and still can not see double vertices. Any suggestions?

Tom

If there are no double vertices prior the extrusion there should be no double vertices after the extrusion.

What cells did you use for extrusion? Shells or fluid cells? How did you fix the negative volumes?

I followed the standard procedure in proam. I built an extrusion surface, checked it, and built the extrusion layer from it. I used the check tool to check for left handed cells, and used it to flip them. All corrected. I then checked for negative volume cells and used cflip cset to correct those.

Tom

I have found the problem for any that are interested. The mesh from which I created the extrusion surface had cracks. This is what caused the double vertices in the extrusion surface.

Tom