IsTraceHandleValid with default FTraceHandles has unexpected behavior on the first frame

Physics - Sep 18, 2018

Because both FWorldAsyncTraceState's CurrentFrame and FTraceHandle are default initialized to 0, on the first frame, if a new Asnc Trace starts all default FTraceHandles will reference the same (now ...

Instanced and skeletal meshes produce an overlap but fail to compute an MTD

Physics - Sep 11, 2018

Instanced and skeletal meshes produce an overlap but fail to compute an MTD, resulting in the logging of "OverlapTest says we are overlapping, yet MTD says we're not" in LevelActor.cpp ComponentEncr ...

Double-Sided Geometry Collision Doesn't Work When Using Set Physics Linear Velocity

Physics - Sep 10, 2018

Double-sided geometry collision doesn't work when using physics set linear velocity. This does not occur when using floating pawn movement or character movement components. Working as expected in 4 ...

Landscape Hole Error in checked PhysX builds

Physics - Sep 4, 2018

When using checked PhysX builds, landscapes with holes generate errors when they shouldn't. ...

Enabling Skeletal Mesh 'Per Poly Collision' crashes the Editor

Physics - Aug 20, 2018

When a Skeletal Mesh isn't assigned, enabling Per Poly Collision on the Skeletal Mesh Component causes the Editor to crash. This issue was reported and tested in 4.20.1 (CL-4233996). This issue was ...

"Enabled per poly collision" under "Support compute skincache" is ON causes a crash at runtime

Physics - Aug 16, 2018

It seems that "Enabled per poly collision" with "Support compute skincache" causes a crash at runtime immediately. We can easily reproduce it with ContentExample. The logs at the crash timing... L ...

Collision preset setting is not reflected correctly in case of original class inheriting Primitive Component

Physics - Aug 15, 2018

Collision preset setting is not reflected correctly in case of original class inheriting Primitive Component. Probably the cause is UPrimitiveComponent :: PostLoad (). Since FCollisionResponse :: U ...

Projects without PhysX not compiling

Physics - Aug 13, 2018

Compiling without "WITH_PHYSX" leads to compile errors. https://udn.unrealengine.com/questions/450489/projects-without-physx-not-compiling.html Projects without PhysX (WITH_PHYSX disabled) will not ...

[CrashReport] <unknown module>!NvClothPROFILE_x64!physx::shdfnd::Array<nv::cloth::`anonymous namespace'::VertexDistanceCount,nv::cloth::NonTrackingAllocator>::growAndPushBack()

Physics - Aug 9, 2018

No user comments in crash group 760 PX_ASSERT((!capacity) || (newData && (newData != mData))); 761 copy(newData, newData + mSize, mData); 762 763 // inserting elem ...

Physics replication is not working correctly and clients receive different results

Physics - Aug 9, 2018

Physics replication is not working properly. The replicated physics are different than what is on the server. The user who reported this issue pointed out this line as well which seems to not do any ...