OK I have a very simple, but large 30M diameter, octohedron with a 25M octohedral hole in the middle, made in Blender. Each of the 8 segments is identical, and consists of 4 quads (8 tris after conversion): two are the inside and the outside edges 0.1m wide, two are the identical faces with the 22.5 deg ends. This is to be the awning round an octablonal structure. I export it from Blender 2.78, using the preset for SL + Static. The .dae file contains what I would expect. In Beta, I import this using the same file for both visual model (High) and Physics. The file is so simple, anything I could make would be just as complex. Looking at the preview of the physics I see that the yellow physics model fits, it is co-incident on all faces and edges, and does NOT cover the hole in the centre. On import without analyse, rez and set to prim, this mesh does NOT, repeat NOT, show a collision surface over the hole using the Render Metadata->Physics Shapes tool in Developer, yet you can walk your avatar over the hole in mid (simulated) air!!!!! As a prim, this comes in at 1.0 download, 1.0 physics, 0.5 server, and 349 display. But is useless. If I do the same thing and Analyse, the physics model is similarly co-incident and now the usual pinky-glow. On import and rez, switch to prim, the mesh behaves as expected and you fall through the hole. The picture seen in Render Metadata->Physics Shapes is IDENTICAL to the one not analysed. But as a prim it is 0.9 download, 2.9 physics, 0.5 server, and 339 Display. Is there a bug in the Render Metadata->Physics Shapes tool? Or better still, is there a tool that actually shows the physics in world?