SOLVED. ok, so here goes. I have been an avid fan of making SSTO's for about a year now, and with the B9 pack and FAR I can take +300t of rocket into LKO. However, there are no cargo bays large enough for that kind of cargo.. So last week I decided to learn to use Blender + Unity to first modify the B9 S2W 6m cargo bay so it could take 3m rocket parts and to make adapters from S2W to what I currently dub S2WD. (D for doubious). On the long term I intend to make B9 compatible parts that can take huge internal payloads and have both top and rear cargobay doors with enough clearance that anything that actually fits the cavity will be able to enter/leave (an issue I have had with MK4 cargo bay doors). But before I can do that, I need to understand what I'm currently doing wrong. I'm using Unity 4, Blender 2.70, part tools 0.23. So what is the problem? Collision meshes. No, what is the real problem? When in the VAB or in flight, only one of the mesh colliders (out of 11) act like a collision mesh in the cargo bay hull part. While the multiple mesh colliders (2) used on the cargo bay doors are correct. (!) detailed: I imported the S2W 6m cargo bay into blender with .mu import script, modified the model by adding 1m of height, made convex mesh colliders (boxes) for all the sidewalls, floors and cargo bay doors. Nope, not one single mesh collider but actually colliders that are individually convex and together match the new S2WD 6m Cargo bay. Nothing.. nada. I've tried a few different approaches by now. 1. I used edge split in blender on the mesh colliders. =nada. 2. I duplicated each mesh collider and inverted the normals of the new duplicate. =nada. 3. I made sure none of the mesh colliders overlap in case that was screwing things up. =nada. 4. I made placeholders for each mesh colliders as actual objects, assigned the placeholders a individual mesh collider, then told Unity to not render the objects. Then mesh collision works correctly but KSP renders the placeholders objects. For me it seems that I am either missing a critical piece of information about mesh colliders. Or there is some sort of trick to making hollow objects. What am I doing wrong? And what can I do to make it easier for you to understand my problem? Here are pictures of the part. The first picture show correct placement of an object on the left side of the part. However, it is not possible to place the same object on the right side. If I however turn on 2-fold symmetry, then the 2nd part is placed correctly. https://www.dropbox.com/sh/4cqcdr46z5iw0ah/AAA5wJq-JP__6xgmpWpQ2BAPa
