UE4 2.7.2 Crash when using VR Mode in Editor

[mauricedietrich0]

Hi there,

we are using the Leap Motion Controller width Gemini in our Project. When I try the Leap Mode VR Unreal Crahses width the following error message:

Assertion failed: !Pose[ParentIndex].ContainsNaN() [File:F:\UE_4.27\Engine\Source\Runtime\Engine\Public\BonePose.h] [Line: 633]

UE4Editor_Core!AssertFailedImplV() [D:\Build++UE4\Sync\Engine\Source\Runtime\Core\Private\Misc\AssertionMacros.cpp:104]
UE4Editor_Core!FDebug::CheckVerifyFailedImpl() [D:\Build++UE4\Sync\Engine\Source\Runtime\Core\Private\Misc\AssertionMacros.cpp:461]
UE4Editor_BodyState!FCSPose::CalculateComponentSpaceTransform() [F:\UE_4.27\Engine\Source\Runtime\Engine\Public\BonePose.h:633]
UE4Editor_BodyState!FCSPose::CalculateComponentSpaceTransform() [F:\UE_4.27\Engine\Source\Runtime\Engine\Public\BonePose.h:630]
UE4Editor_BodyState!FCSPose::GetComponentSpaceTransform() [F:\UE_4.27\Engine\Source\Runtime\Engine\Public\BonePose.h:597]
UE4Editor_BodyState!FAnimNode_ModifyBodyStateMappedBones::EvaluateComponentPose_AnyThread() [C:\Users\momos\Desktop\VRTW\VRTWProj\Plugins\UltraLeapTracking\Source\ThirdParty\BodyState\Private\AnimNode_ModifyBodyStateMappedBones.cpp:199]
UE4Editor_AnimGraphRuntime!FAnimNode_SkeletalControlBase::EvaluateComponentSpace_AnyThread() [D:\Build++UE4\Sync\Engine\Source\Runtime\AnimGraphRuntime\Private\BoneControllers\AnimNode_SkeletalControlBase.cpp:157]
UE4Editor_Engine!FComponentSpacePoseLink::EvaluateComponentSpace() [D:\Build++UE4\Sync\Engine\Source\Runtime\Engine\Private\Animation\AnimNodeBase.cpp:442]
UE4Editor_Engine!FAnimNode_ConvertComponentToLocalSpace::Evaluate_AnyThread() [D:\Build++UE4\Sync\Engine\Source\Runtime\Engine\Private\Animation\AnimNodeSpaceConversions.cpp:38]
UE4Editor_Engine!FPoseLink::Evaluate() [D:\Build++UE4\Sync\Engine\Source\Runtime\Engine\Private\Animation\AnimNodeBase.cpp:356]
UE4Editor_Engine!FAnimInstanceProxy::EvaluateAnimationNode_WithRoot() [D:\Build++UE4\Sync\Engine\Source\Runtime\Engine\Private\Animation\AnimInstanceProxy.cpp:1465]
UE4Editor_Engine!FAnimInstanceProxy::EvaluateAnimation_WithRoot() [D:\Build++UE4\Sync\Engine\Source\Runtime\Engine\Private\Animation\AnimInstanceProxy.cpp:1385]
UE4Editor_Engine!FAnimInstanceProxy::EvaluateAnimation() [D:\Build++UE4\Sync\Engine\Source\Runtime\Engine\Private\Animation\AnimInstanceProxy.cpp:1363]
UE4Editor_Engine!UAnimInstance::ParallelEvaluateAnimation() [D:\Build++UE4\Sync\Engine\Source\Runtime\Engine\Private\Animation\AnimInstance.cpp:728]
UE4Editor_Engine!USkeletalMeshComponent::EvaluateAnimation() [D:\Build++UE4\Sync\Engine\Source\Runtime\Engine\Private\Components\SkeletalMeshComponent.cpp:1874]
UE4Editor_Engine!USkeletalMeshComponent::PerformAnimationProcessing() [D:\Build++UE4\Sync\Engine\Source\Runtime\Engine\Private\Components\SkeletalMeshComponent.cpp:1964]
UE4Editor_Engine!USkeletalMeshComponent::ParallelAnimationEvaluation() [D:\Build++UE4\Sync\Engine\Source\Runtime\Engine\Private\Components\SkeletalMeshComponent.cpp:3756]
UE4Editor_Engine!FParallelAnimationEvaluationTask::DoTask() [D:\Build++UE4\Sync\Engine\Source\Runtime\Engine\Private\Components\SkeletalMeshComponent.cpp:123]
UE4Editor_Engine!TGraphTask::ExecuteTask() [D:\Build++UE4\Sync\Engine\Source\Runtime\Core\Public\Async\TaskGraphInterfaces.h:886]
UE4Editor_Core!FTaskThreadAnyThread::ProcessTasks() [D:\Build++UE4\Sync\Engine\Source\Runtime\Core\Private\Async\TaskGraph.cpp:1066]
UE4Editor_Core!FTaskThreadAnyThread::ProcessTasksUntilQuit() [D:\Build++UE4\Sync\Engine\Source\Runtime\Core\Private\Async\TaskGraph.cpp:889]
UE4Editor_Core!FTaskThreadAnyThread::Run() [D:\Build++UE4\Sync\Engine\Source\Runtime\Core\Private\Async\TaskGraph.cpp:966]
UE4Editor_Core!FRunnableThreadWin::Run() [D:\Build++UE4\Sync\Engine\Source\Runtime\Core\Private\Windows\WindowsRunnableThread.cpp:86]

In the other Modes it doesnt crahs and shows the hand.
Does someone have any idea on why this could be happining.

[fmeinke]

We managed to fix the issue.
The Ultraleap Tracking Content provides a IEPawnHands Blueprint we used as a first guide to working with the Leap Motion Controller. We oriented ouur LeapOptions on the provided example in the SetupForMouseControl(). There LeapOptions.OptionsTransformOriginToHMD was set to true. Unfortunately exactly this setting seems to be problematic in combination with LeapOptions.OptionsMode set to LEAPMODEVR.

In short: Setting LeapOptions.OptionsTransformOriginToHMD = false in SetLeapOptions() when no HMD is connected and the LEAPMODEVR should be used solves the problem.

Note: That applies to the provided blueprint nodes.