Character sliding when changing its Up vector

Character sliding when changing its Up vector

Hello Havok developers,

I am struggling with strange issue regarding character proxy orientation, I would appreciate any help/advice. In my scene, there is a character on moving/rotating platform (keyframed). Character has gravity in down direction of the platform, thus it is still pushed to it.

So far, it works well

My goal is to have a character in correct orientation, but if I set him Up direction to match platform after each simulation step, character begins sliding  on the platform. Moreover, it starts penetrating, which is worse.

I already tried rigid body character, but it is not handling this scenario correctly at all (it is penetrating since platform starts moving).

Thank you for any advice,


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I find out that penetration was caused by missing m_phantom->setTransform according to new Up vector. But still, the character is sliding on the platform :(

Hi Petr,

Are you setting the position of the character manually with hkpCharacterProxy::setPosition()? If so have you tried drawing a cross/star(anything that is just drawn in space and not an entity in the world) at the same location you are setting the character at? This way we can see if you are setting the position incorrectly or if the character is somehow moving from the desired position. HK_DISPLAY_STAR should be helpful for this.

Amy Developer Support Engineer Havok

Hello Amy, I have "fixed" this by switching to rigid body character. Setting maximum friction, character is not moving at all.

Thank you for support, petr

Hi Petr,

I'm glad you found something that is working for you but since I don't know what is going wrong (and therefore why setting max friction is helping as much as it is) this doesn't sound like an optimal solution and it may cause other problems down the line.

It's not my place to tell you how to write your game but I'd definitely recommend trying to understand why the character is sliding when using a normal friction value, as it could save you some trouble later on. If you'd like to investigate this some more, try out my previous suggestion and send us a Visual Debugger movie of the character sliding and we can look into this some more.

Amy Developer Support Engineer Havok

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