I have created a decent number of scenery pieces now (stationary ones that is) and Ive started to notice the odd unusual problem in a few of my creations.
When they are made (in cmd using tool) they create like anything else, however after making them into scenery tags with guerilla and adding them in sapien, when the camera is pointed at certain angles, the effected model disappears. I wouldnt have thought much of it, except the parts that temperarily disappear on the model become walkthroughable upon creating the map. The rest of the model is solid, except that paticular section. I would just start again, but it has been happening a lot recently, and frequently. Any ideas?

Check bounding and render bounding radius values. If you dont know what that means, go to sapien and in console write "debug_objects 1" you will see every collision model and their bounding radiuses as spheres. Sphere must be larger than the model itself.

Also, when tweaking a bounding radius, any part of the model that is outside of the sphere will have no collision, and if it does still collide, it's bad collision that can be jumped through<

I think the sphere also starts at the origin, so try offsetting it to surround your scenery