Adding polygon UVs & Normals.

sheilan

Hello,

I've made a custom binary file format that contains model data similar to .OBJ (vertices, normals, uvs & indices for each triangle)
I've managed to create the polygons with using the vertices via the faces indices, but adding Normals & UVs seems to be a little trickier. I've read the SDK about UVWTag but I can't seem to understand how to translate the two values used for each face (U & V) into a UVWTag via python.

Any help appreciated!

m_adam

Hi @sheilan, UVs and Normals are stored in appropriate tags.
UVs are stored per Polygon Vertex as described in the C++ UVWTag Manual. Find an example in python in this topic.
Normals are stored in the same way, as described in the C++ NormalTag Manual. Find example in python in this topic.

If you have any questions, please let me know and do not hesitate.
Cheers,
Maxime.

sheilan

@m_adam

Thanks a lot!
I've managed to do UV's thanks to the first method, trying my luck with Normals now.

One more thing I'm curious about is Phong Tag. When I'm importing the same mesh in OBJ format, it seems to create Normal tag & Phong tag, both seem to affect the normals of the mesh. Now since I'm working with the same data, should I use the vertex normal data to generate both Normal tag & Phong tag, or would one be enough?

Thanks,
Sheilan.

m_adam

Phong tag is just for the display of the normals. So the viewport interpolates the normal set by the NormalTag.
So basically you have to define the normal in the NormalTag and then apply a Phong tag that will tell the viewport to render how to read these normal data in order to smooth them.

For more information see this following picture, this is the same sphere, same polygon but they get different shading.

Cheers,
Maxime.

sheilan

This post is deleted!

sheilan

Ok I seem to be doing something wrong with the Normals.

Even though the Normal Tag is there, it doesn't seem to be doing anything.
Here's the code (using functions from the post you posted)

# Create UV Tag
uv_tag = c4d.UVWTag(polyCount)
# Create Normal Tag
nrmTag = c4d.NormalTag(polyCount)
# Create Normal List
normalList = []

for f in range(polyCount):
    # Loading & Creating points from the binary file
    ### I chose to not add this part as it's irrelevant

    # Load UV's for first point
    uv1 = vertices_uvs[tri_uvs[0]]
    # Load UV's for second point
    uv2 = vertices_uvs[tri_uvs[1]]
    # Load UV's for third point
    uv3 = vertices_uvs[tri_uvs[2]]
    # Create polygon with 3 points
    mypoly.SetPolygon(f, c4d.CPolygon(surface_vertices[vertex1],surface_vertices[vertex2],surface_vertices[vertex3]))
    # Create poly UV
    uv_tag.SetSlow(f, c4d.Vector(uv1[0], uv1[1], 0),
    
                c4d.Vector(uv2[0], uv2[1], 0),  
    
                c4d.Vector(uv3[0], uv3[1], 0),  
    
                c4d.Vector(0,0,0))  
    
    # Load Normals for first point
    normal1 = vertices_normals[tri_normals[0]]
    # Load Normals for second point    
    normal2 = vertices_normals[tri_normals[1]]
    # Load Normals for third point
    normal3 = vertices_normals[tri_normals[2]]
    
    # Add normals to their points
    a = c4d.Vector(normal1[0],normal1[1],normal1[2])
    b = c4d.Vector(normal2[0],normal2[1],normal2[2])
    c = c4d.Vector(normal3[0],normal3[1],normal3[2])
    d = c4d.Vector() # I tried setting as empty vector or same as C (it's a triangle poly)

    # Add normals to normalList
    normalList.append(a)
    normalList.append(b)
    normalList.append(c)
    normalList.append(d)

# Set normalList to Normal Tag of object
SetAllHighLevelNormals(nrmTag, normalList)
mypoly.Message(c4d.MSG_UPDATE)
# Add object
doc.InsertObject(mypoly,None,None)
doc.AddUndo(c4d.UNDOTYPE_NEW, mypoly)
# Add UV Tag
mypoly.InsertTag(uv_tag)
doc.AddUndo(c4d.UNDOTYPE_NEW, uv_tag)
# Add Normal Tag
mypoly.InsertTag(nrmTag)
doc.AddUndo(c4d.UNDOTYPE_NEW, nrmTag) 

mypoly.Message(c4d.MSG_UPDATE)
c4d.EventAdd()
doc.EndUndo()

I checked one of the normalLists before & after the conversion using the SetAllHighLevelNormals() function and those were the results
before:

[1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, 0.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, 0.0, 0.0, 0.0, -1.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, 0.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, 0.0, 0.0, 0.0, -1.0, 0.0, 0.0]

after:

[32000, 0, 0, 32000, 0, 0, 0, 0, 0, 32000, 0, 0, 32000, 0, 0, 32000, 0, 0, 0, 0, 0, 32000, 0, 0, 0, 32000, 0, 0, 32000, 0, 0, 0, 0, 0, 32000, 0, 0, 32000, 0, 0, 32000, 0, 0, 0, 0, 0, 32000, 0, 0, 0, 32000, 0, 0, 32000, 0, 0, 0, 0, 0, 32000, 0, 0, 32000, 0, 0, 32000, 0, 0, 0, 0, 0, 32000, 0, 33536, 0, 0, 33536, 0, 0, 0, 0, 0, 33536, 0, 0, 33536, 0, 0, 33536, 0, 0, 0, 0, 0, 33536, 0, 33536, 0, 0, 33536, 0, 0, 0, 0, 0, 33536, 0, 0, 33536, 0, 0, 33536, 0, 0, 0, 0, 0, 33536, 0, 0]

UVW Tag works perfectly, Normal Tag doesn't.

Thanks,
Sheilan.

m_adam

This is due to a bug currently affecting NormalMap SetAllHighLevelNormals and GetAllHighLevelNormals the only workaround is the one described in the previous post I posted. This bug is going to be fixed for the next release.

Cheers Maxime

sheilan

@m_adam
I'm getting an error when trying to use the functions he later posted as a workaround.

Here's the updated code

# Create UV Tag
uv_tag = c4d.UVWTag(polyCount)
# Create Normal Tag
nrmTag = c4d.NormalTag(polyCount)
# Create Normal List
normalList = []

for f in range(polyCount):
    # Loading & Creating points from the binary file
    ### I chose to not add this part as it's irrelevant

    # Load UV's for first point
    uv1 = vertices_uvs[tri_uvs[0]]
    # Load UV's for second point
    uv2 = vertices_uvs[tri_uvs[1]]
    # Load UV's for third point
    uv3 = vertices_uvs[tri_uvs[2]]
    # Create polygon with 3 points
    mypoly.SetPolygon(f, c4d.CPolygon(surface_vertices[vertex1],surface_vertices[vertex2],surface_vertices[vertex3]))
    # Create poly UV
    uv_tag.SetSlow(f, c4d.Vector(uv1[0], uv1[1], 0),
    
                c4d.Vector(uv2[0], uv2[1], 0),  
    
                c4d.Vector(uv3[0], uv3[1], 0),  
    
                c4d.Vector(0,0,0))  
    
    # Load Normals for first point
    normal1 = vertices_normals[tri_normals[0]]
    # Load Normals for second point    
    normal2 = vertices_normals[tri_normals[1]]
    # Load Normals for third point
    normal3 = vertices_normals[tri_normals[2]]
    
    # Add normals to their points
    a = c4d.Vector(normal1[0],normal1[1],normal1[2])
    b = c4d.Vector(normal2[0],normal2[1],normal2[2])
    c = c4d.Vector(normal3[0],normal3[1],normal3[2])
    d = c4d.Vector() # I tried setting as empty vector or same as C (it's a triangle poly)

    # Add normals to normalList
    normalList.append(a)
    normalList.append(b)
    normalList.append(c)
    normalList.append(d)

# Set normalList to Normal Tag of object
SetAllHighLevelNormals(nrmTag, normalList)
normalList = GetLowLevelNormals(nrmTag,mypoly)
SetAllHighLevelNormals(nrmTag, normalList)

mypoly.Message(c4d.MSG_UPDATE)
# Add object
doc.InsertObject(mypoly,None,None)
doc.AddUndo(c4d.UNDOTYPE_NEW, mypoly)
# Add UV Tag
mypoly.InsertTag(uv_tag)
doc.AddUndo(c4d.UNDOTYPE_NEW, uv_tag)
# Add Normal Tag
mypoly.InsertTag(nrmTag)
doc.AddUndo(c4d.UNDOTYPE_NEW, nrmTag) 
mypoly.Message(c4d.MSG_UPDATE)
c4d.EventAdd()
doc.EndUndo()

I get TypeError: unsupported operand type(s) for *: 'int' and 'c4d.PolygonObject'
I'm rather confused about what type of variable polygon is in his function as theres no context.

m_adam

Hi @sheilan, NormalTag is a bit special, as I said there is currently a bug in S/GetAllHighlevelData for NormalTag so you need to use S/GetLowlevelDataAddressR/W.

With that's said since you access the low-level data, the current data structure for the normal tag is a list of int16. Then a polygon (whatever if it's a tri or a quad) is represented by 12 int16 such in order to give use 4 vectors (4 vectors x 3 values for each vector = 12 values and in this case 12 int16)

Not sure it's very clear however here it's a code.

"""
Copyright: MAXON Computer GmbH
Author: Maxime Adam

Description:
    - Reads and Write the Raw Data of a Normal Tag.
    - Normals are stored for each vertex of each polygon.
    - Raw Data normal structure for one polygon is 12 int16 value (4 vectors for each vertex of a Cpolygon * 3 component for each vector) even if the Cpolygon is a Triangle.

Class/method highlighted:
    - c4d.NormalTag
    - c4d.VariableTag.GetLowlevelDataAddressR()
    - c4d.VariableTag.SetLowlevelDataAddressR()

Compatible:
    - Win / Mac
    - R13, R14, R15, R16, R17, R18, R19, R20
"""
import c4d
import array


def CreateNormalTag(op):
    """
     Creates a NormalTag on the passed PolygonObject.

    :param op: The PolygonObject that will received a normal Tag.
    :type op: c4d.PolygonObject
    :return: The created tag.
    :rtype: c4d.NormalTag
    """
    # Checks if the passed object is a polygon object.
    if not isinstance(op, c4d.PolygonObject):
        raise TypeError("op is not a c4d.PolygonObject.")
    
    # Retrieves the polygonCount
    polyCnt = op.GetPolygonCount()

    # Creates a Normal Tag in memory only
    normalTag = c4d.NormalTag(polyCnt)
    if normalTag is None:
        raise MemoryError("Failed to creates a normal Tag.")

    # Inserts the tag to the passed object
    op.InsertTag(normalTag)

    # Notifies the object he need to update to take care of the newly created normal tag
    op.Message(c4d.MSG_UPDATE)
    return normalTag


def ReadNormalTag(tag):
    """
    Read the raw data stored in Normal Tag.

    :param tag: The Normal Tag to read the data from.
    :type tag: c4d.NormalTag
    :return: A list with all the raw data.
    :rtype: list[int]
    """
    # Retrieves the read buffer array
    buffer = tag.GetLowlevelDataAddressR()

    # Converts this BitSeq buffer to a list of short int (int16)
    intArray = array.array('h')
    intArray.fromstring(buffer)
    data = intArray.tolist()

    # Returns the data
    return data


def WriteNormalTag(tag, normalList):
    """
    Write the raw data to a Normal Tag.

    :param tag: The Normal Tag to write the data to.
    :type tag: c4d.NormalTag
    :param normalList: A list with all the raw data.
    :type normalList: list[int]
    """
    # Retrieves the write buffer array
    buffer = tag.GetLowlevelDataAddressW()
    if buffer is None:
        raise RuntimeError("Failed to retrieves internal write data for the normal tag.")

    # Translates list of short int 16 to a BitSeq (string are byte in Python 2.7)
    intArray = array.array('h')
    intArray.fromlist(normalList)
    data = intArray.tostring()
    buffer[:len(data)] = data


def main():
    # Checks if selected object is valid
    if op is None:
        raise ValueError("op is none, please select one object.")

    # Checks if the selected object is a polygon object
    if not isinstance(op, c4d.PolygonObject):
        raise TypeError("op is not a c4d.PolygonObject.")

    # Creates a normal tag
    tag = CreateNormalTag(op)

    # Retrieves the raw data stored into the tag (all values will be equal to 0 since we just created the normal tag)
    rawNormalData = ReadNormalTag(tag)

    # Prints the current value stored in tag, since data are stored as int16 and not float you have to divide them by 32000.0
    print [normal / 32000.0 for normal in rawNormalData]

    # Creates a list representing a float gradient value from 0 to 1 then remap these value from float to int16 by multiplying them
    valueToSet = [int(float(normalID) / len(rawNormalData) * 32000.0) for normalID in xrange(len(rawNormalData))]

    # Writes the previous list to the normal tag.
    WriteNormalTag(tag, valueToSet)

    # Reads back the normal stored in the normal tag, value should go from 0 to 1
    print [normal / 32000.0 for normal in ReadNormalTag(tag)]

    c4d.EventAdd()


if __name__ == "__main__":
    main()

So in your case instead to write normals like

# Add normals to their points
a = c4d.Vector(normal1[0],normal1[1],normal1[2])
b = c4d.Vector(normal2[0],normal2[1],normal2[2])
c = c4d.Vector(normal3[0],normal3[1],normal3[2])
d = c4d.Vector() # I tried setting as empty vector or same as C (it's a triangle poly)

# Add normals to normalList
normalList.append(a)
normalList.append(b)
normalList.append(c)
normalList.append(d)

You will have to do

a = [normal1[0],normal1[1],normal1[2]]
b = [normal2[0],normal2[1],normal2[2]]
c = [normal3[0],normal3[1],normal3[2]]
d = [0.0, 0.0, 0.0] # Even if it's a Tri, you should pass a value.

# Add normals to normalList
normalList.extend(a)
normalList.extend(b)
normalList.extend(c)
normalList.extend(d)

# Maps data from float to int16 value
normalListToSet = [int(normal * 32000.0) for normal in normalList]

# Writes the previous list to the normal tag.
WriteNormalTag(nrmTag, normalListToSet)

Hope it helps, if you have any questions, please do not hesitate!
Cheers,
Maxime.

sheilan

Hello @m_adam ,

Skip to the edit below.

────────────────────
Thanks again for the reply but the normal tag still doesn't seem to be doing anything.
Here's how the code looks right now :

# Looping through each surface (polygon object/mesh/model) in the scene
for i in range(surfaceCount):
    #Create new polygon object
    mypoly = c4d.BaseObject(c4d.Opolygon) #Create an empty polygon object
    mypoly.SetName(materialName)
    uv_tag = c4d.UVWTag(triCount)   
    # triCount & materialName are variables I use to store the name of the object + the polycount
    nrm_tag = CreateNormalTag(mypoly,triCount)
    normalList = [] # Fresh new normalList created for each PolygonObject I'm working on

    # loop through each triangle/poly and gather it's data from my binary file
    for f in range(triCount):
        # The points, polys & uv creation part is unnecessary here so I skipped right to normals

        a = [normal1[0],normal1[1],normal1[2]]
        b = [normal2[0],normal2[1],normal2[2]]
        c = [normal3[0],normal3[1],normal3[2]]
        d = [0.0, 0.0, 0.0] 

        # Add normals to normalList
        normalList.extend(a)
        normalList.extend(b)
        normalList.extend(c)
        normalList.extend(d)

    # After we are done looping through the triangles, all polys are created including their points, polygons, UVs & the normalList
    normalListToSet = [int(normal * 32000.0) for normal in normalList] # set of all normals for this polygon object
    WriteNormalTag(nrm_tag, normalListToSet)
    nrm_tag = mypoly.GetTag(c4d.Tnormal) # This is probably unnecessary but I used it just in case

    # Retrieves the raw data stored into the tag
    rawNormalData = ReadNormalTag(nrm_tag)

    # Prints the current value stored in tag, since data are stored as int16 and not float you have to divide them by 32000.0
    print "current data stored in tag - should go from 0 to 1"
    print [normal / 32000.0 for normal in rawNormalData]

    # Creates a list representing a float gradient value from 0 to 1 then remap these value from float to int16 by multiplying them
    valueToSet = [int(float(normalID) / len(rawNormalData) * 32000.0) for normalID in xrange(len(rawNormalData))]

    # Writes the previous list to the normal tag.
    WriteNormalTag(nrm_tag, valueToSet)

    print "new values of normal tag"        
    print [normal / 32000.0 for normal in ReadNormalTag(nrm_tag)]

Now here are results of few of the normal tags in the scene

old data stored in tag

[0.994125, -0.07825, -0.05478125, 0.994125, -0.07825, -0.05478125, 0.994125, -0.07825, -0.05478125, 0.0, 0.0, 0.0, 0.994125, -0.07825, -0.05478125, 0.994125, -0.07825, -0.05478125, 0.994125, -0.07825, -0.05478125, 0.0, 0.0, 0.0, 0.994125, -0.07825, -0.05478125, 0.994125, -0.07825, -0.05478125, 0.994125, -0.07825, -0.05478125, 0.0, 0.0, 0.0, 0.994125, -0.07825, -0.05478125, 0.994125, -0.07825, -0.05478125, 0.994125, -0.07825, -0.05478125, 0.0, 0.0, 0.0]

new data of normal tag

[0.0, 0.0208125, 0.04165625, 0.0625, 0.0833125, 0.10415625, 0.125, 0.1458125, 0.16665625, 0.1875, 0.2083125, 0.22915625, 0.25, 0.2708125, 0.29165625, 0.3125, 0.3333125, 0.35415625, 0.375, 0.3958125, 0.41665625, 0.4375, 0.4583125, 0.47915625, 0.5, 0.5208125, 0.54165625, 0.5625, 0.5833125, 0.60415625, 0.625, 0.6458125, 0.66665625, 0.6875, 0.7083125, 0.72915625, 0.75, 0.7708125, 0.79165625, 0.8125, 0.8333125, 0.85415625, 0.875, 0.8958125, 0.91665625, 0.9375, 0.9583125, 0.97915625]

old data stored in tag

[1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, 0.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, 0.0, 0.0]

new data of normal tag

[0.0, 0.0208125, 0.04165625, 0.0625, 0.0833125, 0.10415625, 0.125, 0.1458125, 0.16665625, 0.1875, 0.2083125, 0.22915625, 0.25, 0.2708125, 0.29165625, 0.3125, 0.3333125, 0.35415625, 0.375, 0.3958125, 0.41665625, 0.4375, 0.4583125, 0.47915625, 0.5, 0.5208125, 0.54165625, 0.5625, 0.5833125, 0.60415625, 0.625, 0.6458125, 0.66665625, 0.6875, 0.7083125, 0.72915625, 0.75, 0.7708125, 0.79165625, 0.8125, 0.8333125, 0.85415625, 0.875, 0.8958125, 0.91665625, 0.9375, 0.9583125, 0.97915625]

old data stored in tag

[-1.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, 0.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0]

new data of normal tag

[0.0, 0.0208125, 0.04165625, 0.0625, 0.0833125, 0.10415625, 0.125, 0.1458125, 0.16665625, 0.1875, 0.2083125, 0.22915625, 0.25, 0.2708125, 0.29165625, 0.3125, 0.3333125, 0.35415625, 0.375, 0.3958125, 0.41665625, 0.4375, 0.4583125, 0.47915625, 0.5, 0.5208125, 0.54165625, 0.5625, 0.5833125, 0.60415625, 0.625, 0.6458125, 0.66665625, 0.6875, 0.7083125, 0.72915625, 0.75, 0.7708125, 0.79165625, 0.8125, 0.8333125, 0.85415625, 0.875, 0.8958125, 0.91665625, 0.9375, 0.9583125, 0.97915625]

old data stored in tag

[-1.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, 0.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.7064375, 0.7064375, 0.0, 0.7064375, 0.7064375, 0.0, 0.7064375, 0.7064375, 0.0, 0.0, 0.0, 0.0, 0.7064375, 0.7064375, 0.0, 0.7064375, 0.7064375, 0.0, 0.7064375, 0.7064375, 0.0, 0.0, 0.0, 0.0]

new data of normal tag

[0.0, 0.0208125, 0.04165625, 0.0625, 0.0833125, 0.10415625, 0.125, 0.1458125, 0.16665625, 0.1875, 0.2083125, 0.22915625, 0.25, 0.2708125, 0.29165625, 0.3125, 0.3333125, 0.35415625, 0.375, 0.3958125, 0.41665625, 0.4375, 0.4583125, 0.47915625, 0.5, 0.5208125, 0.54165625, 0.5625, 0.5833125, 0.60415625, 0.625, 0.6458125, 0.66665625, 0.6875, 0.7083125, 0.72915625, 0.75, 0.7708125, 0.79165625, 0.8125, 0.8333125, 0.85415625, 0.875, 0.8958125, 0.91665625, 0.9375, 0.9583125, 0.97915625]

Could this happen because I don't use Phong Tag?

Edit:

Yes it was definitely Phong Tags! Also, this was enough using my initial normal data

# Maps data from float to int16 value
normalListToSet = [int(normal * 32000.0) for normal in normalList]
        
# Writes the previous list to the normal tag.
WriteNormalTag(nrm_tag, normalListToSet)

Anyway, I imported an .obj file that shares the same data as my binary file, and once I copied the Phong Tag settings and applied to my generated objects it was identical, which means Normal Tags are correct!

I can't seem to find a page for Phong Tag though. How would I create a new Phong Tag, and set it's values?

Your help has already done a lot and I really appreciate your responses.
Thanks,
Sheilan.

m_adam

Phong tag are common tags, (data count stored does not change), so you have to create them with the usual way.

tPhong = c4d.BaseTag(c4d.Tphong)
op.InsertTag(tPhong)

or either

op.MakeTag(c4d.Tphong)

You can find the list of all the tags symbols in Tag Types and I recommend you to read the C++ BaseTag and VariableTag Manual to understand the difference between both.

Cheers,
Maxime.

sheilan

Well then that'll be it. Thanks a lot for all the help!
I'll definitely read the manual to get a better idea of each tag.

Here is the final, working code to anyone who reads this thread having the same problems:

def CreateNormalTag(op,polyCnt):
    """
     Creates a NormalTag on the passed PolygonObject.

    :param op: The PolygonObject that will received a normal Tag.
    :type op: c4d.PolygonObject
    :return: The created tag.
    :rtype: c4d.NormalTag
    """
    # Checks if the passed object is a polygon object.
    if not isinstance(op, c4d.PolygonObject):
        raise TypeError("op is not a c4d.PolygonObject.")
    

    # Creates a Normal Tag in memory only
    normalTag = c4d.NormalTag(polyCnt)
    if normalTag is None:
        raise MemoryError("Failed to creates a normal Tag.")

    # Inserts the tag to the passed object
    op.InsertTag(normalTag)

    # Notifies the object he need to update to take care of the newly created normal tag
    op.Message(c4d.MSG_UPDATE)
    return normalTag
def WriteNormalTag(tag, normalList):
    """
    Write the raw data to a Normal Tag.

    :param tag: The Normal Tag to write the data to.
    :type tag: c4d.NormalTag
    :param normalList: A list with all the raw data.
    :type normalList: list[int]
    """
    # Retrieves the write buffer array
    buffer = tag.GetLowlevelDataAddressW()
    if buffer is None:
        raise RuntimeError("Failed to retrieves internal write data for the normal tag.")

    # Translates list of short int 16 to a BitSeq (string are byte in Python 2.7)
    intArray = array.array('h')
    intArray.fromlist(normalList)
    data = intArray.tostring()
    buffer[:len(data)] = data

# Some of the data was read in a binary file/determined earlier but the variable names should be enough to tell what they are
for i in range(surfaceCount):
        # Surface triangles count
        triCount = read_ushort(c2m)
        # Surface Material Name
        materialName = read_string(c2m)
        tri_vertexgroups = {}
        tri_uvgroups = {}
        tri_normalgroups = {}
        for f in range(triCount):
            vertex = vertex1,vertex2,vertex3 # pre-loaded 3 vertex indices for current face
            uv = uv1,uv2,uv3 # pre-loaded 3 UV indices for current face
            normal = normal1,normal2,normal3 # pre-loaded 3 normal indices for current face

            # Add them to a dictionary
            tri_vertexgroups[f] = vertex
            tri_uvgroups[f] = uv
            tri_normalgroups[f] = normal

        # Create dictionary for surface's vertices
        surface_vertices = {}
        # Unique vertex index (used to avoid creating the same vertex twice)
        unique_vertex = 0

        # Create new poly
        mypoly = c4d.BaseObject(c4d.Opolygon) #Create an empty polygon object
        mypoly.SetName(materialName) 
        uv_tag = c4d.UVWTag(triCount)   
        nrm_tag = CreateNormalTag(mypoly,triCount)
        phong_tag = c4d.BaseTag(c4d.Tphong)
        phong_tag[c4d.PHONGTAG_PHONG_ANGLELIMIT]=True
        phong_tag[c4d.PHONGTAG_PHONG_ANGLE]=c4d.utils.Rad(25.5)
        phong_tag[c4d.PHONGTAG_PHONG_USEEDGES]=True
        normalList = []
        # Loop through number of triangles
        for f in range(triCount):
            # Load vertices for current triangle from the list of polygon's vertices
            tri_vertices = tri_vertexgroups[f]

            # Load each vertex of the triangle from a dictionary with all the UVs in the scene using it's index
            vertex1 = vertices_positions[tri_vertices[0]]
            vertex2 = vertices_positions[tri_vertices[1]]
            vertex3 = vertices_positions[tri_vertices[2]]

            # Check if vertex was not added already, add if not.
            if vertex1 not in surface_vertices:
                # Add vertex1 to surface(polygon object)'s dictionary, with a unique index
                surface_vertices[vertex1] = unique_vertex
                unique_vertex += 1
                # Resize our object to allow another point to be created
                mypoly.ResizeObject(unique_vertex, triCount)
                # Create new point
                mypoly.SetPoint(surface_vertices[vertex1],c4d.Vector(vertex1[0],vertex1[1],vertex1[2]))

            if vertex2 not in surface_vertices:
                surface_vertices[vertex2] = unique_vertex
                unique_vertex += 1
                mypoly.ResizeObject(unique_vertex, triCount)
                mypoly.SetPoint(surface_vertices[vertex2],c4d.Vector(vertex2[0],vertex2[1],vertex2[2]))

            if vertex3 not in surface_vertices:
                surface_vertices[vertex3] = unique_vertex
                unique_vertex += 1
                mypoly.ResizeObject(unique_vertex, triCount)
                mypoly.SetPoint(surface_vertices[vertex3],c4d.Vector(vertex3[0],vertex3[1],vertex3[2]))

            # Load UVs for current triangle from the list of polygon's UVs
            tri_uvs = tri_uvgroups[f]
            
            # Load each UV of the triangle from a dictionary with all the UVs in the scene using it's index
            uv1 = vertices_uvs[tri_uvs[0]]
            uv2 = vertices_uvs[tri_uvs[1]]
            uv3 = vertices_uvs[tri_uvs[2]]

            # Create polygon(triangle)
            mypoly.SetPolygon(f, c4d.CPolygon(surface_vertices[vertex1],surface_vertices[vertex2],surface_vertices[vertex3]))
            # Add our UV data to the UV tag
            uv_tag.SetSlow(f, c4d.Vector(uv1[0], uv1[1], 0),
                        c4d.Vector(uv2[0], uv2[1], 0),  
                        c4d.Vector(uv3[0], uv3[1], 0),  
                        c4d.Vector(0,0,0))  

            # Load normals for current triangle from the list of polygon's normals
            tri_normals = tri_normalgroups[f]

            # Load each normal of the triangle from a dictionary with all the normals in the scene using it's index
            normal1 = vertices_normals[tri_normals[0]] # Vector3 of normal direction
            normal2 = vertices_normals[tri_normals[1]]
            normal3 = vertices_normals[tri_normals[2]]
            normal4 = [0.0, 0.0, 0.0]  # Even if it's a Tri, you should pass a value.

            # Add normals to normalList
            normalList.extend(normal1)
            normalList.extend(normal2)
            normalList.extend(normal3)
            normalList.extend(normal4)
            
        # Maps data from float to int16 value
        normalListToSet = [int(normal * 32000.0) for normal in normalList]

        # Writes the previous list to the normal tag.
        WriteNormalTag(nrm_tag, normalListToSet)

        doc.InsertObject(mypoly,None,None)
        mypoly.Message(c4d.MSG_UPDATE)
        mypoly.InsertTag(uv_tag)
        mypoly.Message(c4d.MSG_UPDATE)
        mypoly.InsertTag(phong_tag)
        mypoly.Message(c4d.MSG_UPDATE)
        
        c4d.EventAdd()

Thank you once again Maxime, your help is appreciated!

m_adam

Just to add additional information,

In R21 GetAllHighlevelData() and SetAllHighlevelData() are working as expected for NormalTag, so data are not any more "shifted" and correctly interpreted internally.

See What's New: Fixes:

Fixed an issue where VariableTag.GetAllHighlevelData() and VariableTag.SetAllHighlevelData() used Uint16 instead of int16 for Tnormal.
Fixed an issue where VariableTag.GetAllHighlevelData() returned data were shifted and not complete for Tnormal.

Cheers,
Maxime.