I can't upload an fbx or blender project file to the discussion so here's a google drive link for the grass planes: https://drive.google.com/open?id=1OcPbHVgOgJ79G58SHWMlI0e1gXxzeNAf You use a normal edit modifier to change the direction of all of the normals.
What type of decals are we talking about? Stickers? Ones that modifies normal?Or? If its stickers, you can slap a plane where you want the decal and give it some unique uv shape or an atlas uv with separate material.
Been progressively working through and getting all the plates in a state where they have nice low poly topology that can easily be modified and subdivided. I also started working on the Stormbreaker Axe head over my lunch today:
The main thing is that you can render a standard material which is set to show in viewport and the rendered frame actually matches 100% what you see in the viewport. Just don't reset your normals through edit normals modifier. ;-)
Started working on a tiling floor material. About 3 hours spend on it. Modeled a highpoly, baked it on a plane, added a few rivets with NDO and threw it in DDO. Did not do any painting yet, these are all slightly modified smart materials.
Relax modifier on a selection. If that's not good, I would simply remodel it from scratch. A lot faster than fiddling around trying different tricks. You could also look for EdgeStraighten script (on my phone so can't check).
Finished the sculpt and did some texture experiments. Diffuse Map is: base colors + AO (multiply) + NormalGreenChannel (overlay & modified) + some minor tweaks (and copy pasted moon decals^^). I think that's a good start and I will work on from this.
Make a plane, make a two holes, copy it many times end to end, weld the points, bend then smooth, or smooth then bend, depends how you wanna do it. Sorry if this is a poor explanation. Don't forget to throw in a shell modifier.
Thank you very much guys. @ Mekhollandt you got me there I have a copy of the mesh previous to apply the smooth and made the low from that copy, guess I have to modify my workflow one more time.
If that happens to not be the problem try downloading the latest update for your version of Max. Max 2012 shipped with a bug that broke the skin modifier. http://usa.autodesk.com/adsk/servlet/ps/dl/index?siteID=123112&id=2334435&linkID=9241178