Particle shape movement after landing

So I’m following a tutorial from blenderguru i am at the point where he is creating the shapes for the particles to fly out around 20:20 into the video. I have created them like he has done with the origin of the “rocks” along the x-axis and shaped them accordingly, however i get a strange effect of the particles all wanting to rotate to a certain angle making the effect look very strange. Also they are half-phased through the plane, which in blenderguru’s video they are not. Please if there is anything I can do to fix this or any ideas any of you might have i would love to hear them.:eyebrowlift:

I am not too sure without seeing it, but it sounds like a collision bounds problem.

Go to Game (at the top bar) and enable “Show Physics Visualization”. You will see some crazy lines the next time you start the BGE. Look carefully at the white and green lines, as these sketch out the physics representations of your objects. I can almost guarantee you can see something screwy going on.

You will need to do some thinking to get it all right. I don’t know what your rocks are shaped like, but I would assume changing Collision Bounds types for them to Convex Hull. This will create a shrinkwrapped mesh around the shape. If this is too bar-of-soapy for your needs, you might have to upgrade to the full Triangle Mesh. It is higher resolution, so more accurate but more of a resource hog (which generally only matters if you’re doing real-time stuff).

Oh, and be sure to Apply Scale habitually. Unapplied scales will surprise you in this task as well as many others. In fact I’m in favor of a warning triangle icon whenever there is an unapplied scale. Maybe a question mark, too, when it is nonuniform. I am only 10% joking.

So, there is more to say but this should give you a start.


thank you so much i played with the physics of the particles a bit and found that putting the rotation on random instead of spin helped a bit and also size deflect stopped them from half phasing so ill have to go into what the collision bounds and play around with it until its fixed. Thanks again though, helped a lot.