Physix: Object/Ball does not accelerate when rolling down

Currently i am facing a strange problem. I have set my first objects to “Simulate Physics”. It’s just a ball which is suposed to roll down a surface. However, it does not accelerate, and keeps a steady and slow movement.

Someone has an idea why this happens? IIRC i had no similar problems in other engines using PhysX.(But that was a while ago)


Physics is sensitive to the scale of your object. Your simulation looks like a small boulder rolling down a distant hill so I’m guessing the scale is quite large. If you want it to act more like a marble, then you have to scale things down.

You should check you Physical Material setup for ball and the field. The reason of such behaviour that friction value is hight.

P.S. - Also I would recommend you to make flat horizontal field with physics field to simulate the slope via acceleration force. While working on Hobbit Pinball I’ve tried different approaches and found that it’s the best one :wink:

Yeah, seems like you need to set up Physics Material.

As others have said, it is a bit hard to tell what scale you are working at. You may have too much damping on your ball. Does it move slowly if it is just falling through space? PhysX also has a ‘max angular velocity’ setting which we will expose to the UI in the next release.

Thanks for the answers. I’ll look into the material settings. I used some of the predefined engine one, but it seems i need to define one myself for the wanted behaviour.
I’ll try that out and report my results.

@Ufna thanks, i’ll keep on using this aproach. (I tried out both techniques, only the slope one is shown here). For the force, i added a BP which adds a steady force to the ball into the given direction i wanted to simulate. How did you do it?

The scale:
Shapes->Ball->Scale 0.5 on all axis