lowell wrote:I had been using the "wall sections" to make the insides "solid" so as the Darwinians wouldn’t get stuck inside, plus virii can slip under walls.
The solidity of models is affected by the smoothness of the ground on which they are placed. I have one model which is solid when placed on a flat area, but permeable when placed on rough ground.
My test model is the Cylinder02 fragment from fuelstation.shp with the tank fragment lowered to ground level. The tank was never intended to be "solid" since it was up in the air, but it is perfectly solid on flat ground. It works best when the vertical panels are pushed into the ground a ways.
I am convinced that squads detect collisions only at their feet. If there is a small local gap between the bottom of a model and the ground, then squads can "enter" the building there. Once inside they can exit anywhere. The direction of the normals may be important too -- i.e. is the model sloping in or out at the ground contact.
Squads normally pay attention to the slope of the ground, and the slopes of ground triangles are the same "sign" everywhere. If your model has the reverse slope at ground level, then the squads my not respond properly. I think the building models probably get treated like they are terrain triangles for the purposes of collision detection. A single mode of interaction, so the code is simple. So make sure your model doesn't do things that terrain never does... at least not at the base where it must touch the ground triangles.
I haven't played with this much yet, but I'd be willing to bet that your models would become solid if you extend them down into the ground a bit more and fix any underhangs. Position the sceneroot origin above the base of the model. Most Darwinia models appear to do this, esp. the anthills since they are often placed on uneven terrain.
The render mode used in the shape files has nothing to do with building solidity. The anthills use triangles lists, while the Cylinder02 fragment above uses triangle strips. Both act solid when they contact the ground properly.