# VehicleSDK, HeightField and PxVehicleIsInAir = true

**URL:** <https://forums.developer.nvidia.com/t/vehiclesdk-heightfield-and-pxvehicleisinair-true/57465>\
**Category:** Physics Modeling (closed)\
**Created:** [January 25, 2018, 9:04pm UTC](https://forums.developer.nvidia.com/t/vehiclesdk-heightfield-and-pxvehicleisinair-true/57465 "2018-01-25T21:04:18Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![maxim.goncharenko](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@maxim.goncharenko](https://forums.developer.nvidia.com/u/maxim.goncharenko)\
**Post date:** [January 25, 2018, 9:04pm UTC](https://forums.developer.nvidia.com/t/vehiclesdk-heightfield-and-pxvehicleisinair-true/57465/1 "2018-01-25T21:04:18Z")

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I use Vehicle SDK (Physx SDK 3.4.1)  
In my applicatation vehicles move on a heightfield.  
Vehicle from respawn start to move well, but  
at any point it can stops. And it can not begin to move anymore.  
At this moment PxVehicleIsInAir returns true, but Physx Visual  
Debugger shows another. PVD shows the points of  
contact of the wheels with heightfield.

What should I check ?

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**Author:** ![gyeoman](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/gyeoman/32/10078_2.png) [@gyeoman](https://forums.developer.nvidia.com/u/gyeoman)\
**Post date:** [January 26, 2018, 10:26am UTC](https://forums.developer.nvidia.com/t/vehiclesdk-heightfield-and-pxvehicleisinair-true/57465/2 "2018-01-26T10:26:01Z")

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Does pvd show a rigid body contact or a raycast hitting the heighfield? If you see a rigid body contact then the problem is easily fixed. The wheels should be supported by raycasts but not by rigid body contact. This suggests an issue with the collision filtering on the wheel shapes. They need to be configured to suppress contact.

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<div class="post-metadata">

**Author:** ![maxim.goncharenko](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@maxim.goncharenko](https://forums.developer.nvidia.com/u/maxim.goncharenko)\
**Post date:** [January 29, 2018, 8:54pm UTC](https://forums.developer.nvidia.com/t/vehiclesdk-heightfield-and-pxvehicleisinair-true/57465/3 "2018-01-29T20:54:52Z")

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It working! Thanks!