Morph Target Normals

[Anonymous]

Hi again,

I have a problem in reading the normals info stored per Morph targets.

This is the code that I'm using, from the samples:

int lBlendShapeCount, lBlendShapeChannelCount, lTargetShapeCount;
FbxBlendShape* lBlendShape;
FbxBlendShapeChannel* lBlendShapeChannel;
FbxShape* lShape;

for (int lBlendShapeIndex = 0; lBlendShapeIndex < lBlendShapeCount; ++lBlendShapeIndex)
{
	lBlendShape = (FbxBlendShape*)pMesh->GetDeformer(lBlendShapeIndex, FbxDeformer::eBlendShape);
	lBlendShapeChannelCount = lBlendShape->GetBlendShapeChannelCount();
	for (int lBlendShapeChannelIndex = 0; lBlendShapeChannelIndex < lBlendShapeChannelCount; ++lBlendShapeChannelIndex)
	{
		lBlendShapeChannel = lBlendShape->GetBlendShapeChannel(lBlendShapeChannelIndex);
	
		lTargetShapeCount = lBlendShapeChannel->GetTargetShapeCount();
		for (int lTargetShapeIndex = 0; lTargetShapeIndex < lTargetShapeCount; ++lTargetShapeIndex)
		{
			lShape = lBlendShapeChannel->GetTargetShape(lTargetShapeIndex);


			int j, lControlPointsCount = lShape->GetControlPointsCount();
			FbxVector4* lControlPoints = lShape->GetControlPoints();
			FbxLayerElementArrayTemplate<FbxVector4>* lNormals = NULL;

bool lStatus = lShape->GetNormals(&lNormals);

[...]

The problem is:

lStatus always returns true, but the values are all 0.0!

I check the ASCII version of my FBX file and there are non 0 values in the propriety "normals" of each shape!

Where is my error?

[Anonymous]

I've made some more tests using the original ImportScene sample from the FBX SDK package.

I'm using Visual Studio 2015 debugger to read the various values from vars during the execution:

Results are that

bool lStatus = lShape->GetNormals(&lNormals);

is always full of 0.0s...

but

If I check the values inside lNormals:

Under fbxsdk::FbxLayerElementArray this is what I find: (var name / value / type, separated by a tab)

-		__vfptr	0x00cbc07c {ImportScene.exe!const fbxsdk::FbxLayerElementArrayTemplate<class fbxsdk::FbxVector4>::`vftable'} {...}	void * *
		[0]	0x001c4b50 {ImportScene.exe!fbxsdk::FbxLayerElementArrayTemplate<class fbxsdk::FbxVector4>::`vector deleting destructor'(unsigned int)}	void *
		[1]	0x001bc180 {ImportScene.exe!fbxsdk::FbxLayerElementArray::GetLocked(enum fbxsdk::FbxLayerElementArray::ELockMode,enum fbxsdk::EFbxType)}	void *
		[2]	0x001bc3b0 {ImportScene.exe!fbxsdk::FbxLayerElementArray::Release(void * *,enum fbxsdk::EFbxType)}	void *
		[3]	0x001bc610 {ImportScene.exe!fbxsdk::FbxLayerElementArray::GetStride(void)const }	void *
		[4]	0x001bd610 {ImportScene.exe!fbxsdk::FbxLayerElementArray::ConvertDataType(enum fbxsdk::EFbxType,void * *,unsigned int *)}	void *
		mDataType	eFbxDouble4 (15)	fbxsdk::EFbxType
		mStatus	eSuccess (0)	fbxsdk::LockAccessStatus::ELockAccessStatus
		mReadLockCount	0	int
		mWriteLock	false	bool
		mImplementation	0x01d3d808	void *
		mStride	32	unsigned int
		mDirectLockOn	0	int
		mDirectAccessOn	false	bool
-		mConvertedData	{mSize=0 mCapacity=0 mArray=0x00000000 {???} }	fbxsdk::FbxArray<void *>
		mSize	0	int
		mCapacity	0	int
-		mArray	0x00000000 {???}	void * *
			<Unable to read memory>	void *

mConvertedData-->mArray with question marks is what puzzles me more...

Any help is much appreciated.

Thanks!

[Anonymous]

The FBX file I'm using is here:

https://rapidshare.cc/getfile/code/a52e692ed53fca2d6a0ac04943bd5e64

[Anonymous]

Could at least someone confirm that this is not a BUG? Someone who correctly extracted shapes normal data from an FBX... thanks!

[Numerator]

I am not able to load the file you posted.  I won't load into Maya nor the ImportScene SDK example.  Can you verify the FBX file?

[Anonymous]

That's strange. I just downloaded from the above link and open it in Maya 2015 without any problem.

The file was saved in Maya 2015, FBX plugin version 2015.1

    File Version: 7.4.0
    File Creator: FBX SDK/FBX Plugins version 2015.1
    File Custom writer: No
    File Creation Time: 2015/11/10  10:4:49
    File Axis Direction: Y-up (RH)
    File Units: Centimeters    
    System Axis Direction: Y-up
    System Units: Centimeters
    System frame rate: 30
    File frame rate: 30
    File content: 3 Elements, 18 Materials, 34 Textures

And I use FBX SDK version 2016.1.2 to load in my C++/CLI program.

[Numerator]

The first download must have gotten corrupted. I tried again and it loaded properly.  It's a huge number of triangles, perhaps in the future you can strip the file to bare minimum to make it easier to debug.

I confirm that the normals are are reading 0,0,0

[Anonymous]

Many thanks for your reply.

If you open that file in Maya and then save it in FBX ASCII, looking into the file using any text editor, you'll find normal values for each blend shape that are NOT (0, 0, 0) ...

(If you then use the FBX SDK on the ASCII version, it should return again normals as (0, 0, 0))

... that's why I'm supposing there should be a bug somewhere...

[Numerator]

I could get legitmate normals from the blend shape, but not the target, if that helps. 

			FbxGeometry* geom = lBlendShape->GetGeometry();
			int lControlPointsCount = geom->GetControlPointsCount();

			for (int l = 0; l < geom->GetLayerCount(); l++)
			{
				FbxLayerElementNormal* pLayerNormals = geom->GetLayer(l)->GetNormals();


				FbxLayerElement::EMappingMode normalMappingMode = pLayerNormals->GetMappingMode();
				FbxLayerElement::EReferenceMode normalReferenceMode = pLayerNormals->GetReferenceMode();
				switch (normalMappingMode)
				{
				case FbxLayerElement::eByControlPoint:
				{
					for (int controlPointIndex = 0; controlPointIndex < lControlPointsCount; controlPointIndex++)
					{
						FbxVector4 normal = pLayerNormals->GetDirectArray().GetAt(controlPointIndex);

						Display3DVector("            Normal Vector: ", normal);

					}
					break;
				}
				default:
					break;
				}

			}

[Anonymous]

Thanks a lot for trying. I hope someone could explain me why target normals cannot be read...

[Numerator]

Try this:

				FbxGeometry* geom = lShape->GetBaseGeometry();
				int lControlPointsCount = geom->GetControlPointsCount();

				for (int l = 0; l < geom->GetLayerCount(); l++)
				{
					FbxLayerElementNormal* pLayerNormals = geom->GetLayer(l)->GetNormals();


					FbxLayerElement::EMappingMode normalMappingMode = pLayerNormals->GetMappingMode();
					FbxLayerElement::EReferenceMode normalReferenceMode = pLayerNormals->GetReferenceMode();
					switch (normalMappingMode)
					{
					case FbxLayerElement::eByControlPoint:
					{
						for (int controlPointIndex = 0; controlPointIndex < lControlPointsCount; controlPointIndex++)
						{
							FbxVector4 normal = pLayerNormals->GetDirectArray().GetAt(controlPointIndex);

							Display3DVector("            Normal Vector: ", normal);

						}
						break;
					}
					default:
						break;
					}

				}

Documentation:

/** Get the base geometry of this target shape.
* \return a pointer to the base geometry if set or NULL.
* \remarks Since target shape can only connected to its base geometry through
* blend shape channel and blend shape deformer.
* So only when this target shape is connected to a blend shape channel,
* and the blend shape channel is connected to a blend shape deformer,
* and the blend shape deformer is used on a base geometry, then to get
* base geometry will success.
*/

[Anonymous]

That was one of my experiments... It returns the normals of the unmorphed base mesh, which is not exactly what I need.

I'm more oriented in recomputing the normals for each shape using some known alghoritm. But still I'm curious:

1. The maya FBX plugin exports morphs' normals in a wrong way. For example it uses the base mesh normals instead of the correct ones, and then the FBX SDK fills the normals array with the difference between the base and the target values, which turns out to be (0, 0, 0).
2. There is a bug sort of in the FBX SDK.
3. I'm dumb, and missing some important point.

[Anonymous]

1-3 are question sort of, not statements.

[Numerator]

It looks like a bug.  In the debugger, the normal layer looks to have a size of zero

[Anonymous]

How to report it? (And have Autodesk's confirmation also)

[Anonymous]

I've just been reporting bugs here. Every now and then, one of the posts will get a reply from staff saying they logged it.

[Numerator]

Are you a member of the beta FBX SDK area?  I think there is a way to formal way to file issues there, also.

There is something else I found.  In the FBX ascii file, there are 5269 control points, 15807 vertices and 15807 normals for the target shapes.  From that data, I would think that the normals should be eByPolygonVertex and the count should be 15807, but the normal count from the SDK is 5269 and mapped as eByControlPoint.

As a possible workaround, can you change the way you are creating normals to actually be eByControlPoint in the FBX file?

[Anonymous]

I've noticed that mismatch too... But I was unsure if it could have been the issue or just misleading. The FBX is exported using maya plugin, I don't know how to modify it if the SDK is unable to read it correctly...

[Numerator]

Some one else is having the same issue.   I filed a bug in the beta area and pointed to both threads.

[viviane.rochon]

Hi kors,

I am logging this issue as FBXX-1048. I cannot acces the file you posted. Could you please send it to me directly, so that I can attach it to the logged issue?

viviane.rochon (at) autodesk.com

Thanks!