Getting Zbrush into the mix

Hi forum members,

I have yet another question regarding best practices when getting Zbrush into the mix. I’ve had difficulties with the following approach. I need a cave at the bottom of a moon crater so I exported an obj. from Unity terrain as a sculpt reference object in Zbrush. I intend to use a portion of the obj. to make a cave mesh; then back in Unity flatten the terrain where the geometry originated and fit the cave back into place like a volumetric puzzle piece. It basically works but getting the pieces to fit well is a challenge. (I’m not matching vertices; I’m pulling sides up over one another). I decided to use Zbrush to add new details to the original Unity heightmap by altering the terrain obj. area that borders the cave geometry and run the resulting Zbrush alpha grab doc. .tiff through WM for a slight erosion pass. But when I do this the new WM height map results in Unity terrain that no longer fits the complimentary cave mesh as it once did. The altitude extents is larger : crater rim and base now extend both above and below the original y coordinates. Does anybody have some suggestions on maintaining control and accuracy for a Geometry/Terrain blend landscape. Did I open up a can of worms by using zbrush to create an intermediary .tiff? Any thoughts would really be appreciated. Thanks!

Probably a better idea to cut a hole in the terrain, model your cave and just cover the transition between the terrain and cave with rocks or something. Here’s a tutorial (use google translate): http://www.smokymonkeys.com/kyrill/index.asp?direct=22

Thanks for the reply Althaen,
I hadn’t heard of the shader approach the tutorial takes- I noticed after looking over it that there’s a forum thread at the Unity site devoted to using such a shader. It looks very interesting and I’m psyched to give it a try- thanks very much. I’ll also wind up messing around with Zbrush/ W.M. workflows. To my mind there is surprisingly little detailed information on the net for iterating between World Machine and Zbrush. I’ve definitely seen some tutorials using Mudbox.

Anyhow, thanks again for the lead.

best

manya.proshkina@mail.ru