BGE physics crashes when selecting "Triangle Mesh" as collision shape

Dear fellow Blenderheads,

I have created a very simple BGE test scene, using two “character” objects, a floor plane, and some controllers to move one of the “characters”. Collision detection is important, and should be as exact as possbile, so I selected “Triangle Mesh”. However, when I now press [P] to play the game, Blender 2.72a crashes. No error, no console output, it just vanishes. What am I doing wrong?

Here is my Blender-crashing file: bge_test.blend (97 KB)

Thanks for any hints,
Sybren

Triangle Mesh conflicts with Character every other build. The bottom idea is to not use Triangle Mesh on a Character object.
In my experience, Convex Hull is a good substitute.

The character physics type is best if you don’t know python,

what behaviors do you wish to display?

chances are I can code something in python in a moment for you.

lock X axis?

own.worldPosition.x*=.05

you can cap speed with


if own.localLinearVelocity.(x,y or z)>(top speed):
    own.localLinearVelocity.(x,y or z)*=.9

anything is possible without the character physics type, you just need to write it.

The problem is that “Convex Hull” is not the convex hull, but a bounding axis-aligned box. You can see this in this screenshot:


This is not what I want - I want an actually precise collision detection.

I’ve been using Python for 8 years now, and I’m using it daily, so that’s not the issue. Thanks for your offer to create something for me, though, I really appreciate that.

What I want is to have proper collision detection, and some way of pushing other, similarly shaped objects. I should be able to write the pushing behaviour myself, as long as I have exact enough collision detection and penetration depth/vector information. An axis-aligned bounding box is not precise enough by a long shot.

Drop the object onto the plane at different angles and you’ll see that convex hull is different from a simple box (I don’t think the physics visualization has proper support to display the bounds type).

you can parent sensors to each bone, then detect collision on them, and then define reactions,

or you can have a walking ragdoll…

or you can use compound, and parent things to it, that are simple bounds (sphere box etc) (note: colliding with the child=colliding with the parent)

Thanks for the info, I see I have much to try out :slight_smile:

I’ve created a bug report about the crash: https://developer.blender.org/T42363