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I've been trying to make a realtime steerable car with drivers in Blender and it's starting to work but the only problem now is that Blender makes cache when I play the timeline and then when I reset the timeline it doesn't reset the cache.

I cannot steer any more because Blender has already done the simulation and stored the cache and used that instead of doing a new simulation where I change the drivers to steer differently. If I do end up making an animation with this, I would rather keyframe the drivers instead of baking or replaying from the cache.

So my question is how do I delete the cache in Blender 3.2.2? I cannot figure out where to go and also is it possible to prevent Blender from making cache when the timeline runs?

Chris
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Ga1lus
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1 Answers1

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The cache is different than a baked cache. Bakes can be freed in properties/scene/rigid body world/cache->delete all bakes.

Blender does not not have a "free cache" operation for physics that is available to the user. (There is probably a scriptable operation, but I don't know it.) Blender seems to be operating under the philosophy that it is smart enough to reset the cache when it should be reset, therefore no explicit user operation is necessary.

Mostly, this is the case. For example, Blender resets the cache whenever a rigid body is reoriented. There's no need to reset the cache when nothing has changed, because the rigid body physics will play out exactly as they did in the cache, that's why the cache exists....

However, every once in a while, Blender isn't smart enough to realize that the cache needs to be reset. It's a bit of a moving target; those circumstances tend to change with version.

Whenever these circumstances come up for me, I force a cache reset by starting a cancelling a grab operation on a rigid body: 'g' to start a translation, then 'esc' cancelling out of it.

Nathan
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  • I am having this problem as well and I am afraid the above method is not working. I tested the setup using an animation with collision, and even with animation completely deleted from the project the rigid body system is acting as if it was collided with. Worse, because I tested before duplication, it is remembering the collision on each individual part of the system rather than recalculating for the whole system. – DrIgnatiusCole Aug 31 '23 at 17:17
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    I have encountered some bugs with the cache, particularly with other systems like GN. There was one file where I could come up with no solution other than rebuilding my meshes + physics. If you want to post a question with an attached file, it's possible somebody may be able to help you. – Nathan Aug 31 '23 at 17:23