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Week 14: Oliver and more Matrices

This week's character is Oliver. He wears a magical headband that always flaps in the wind even when there is no wind.


So far he is one of the characters that has changed the least after the initial VR sculpt in Adobe Medium. Here you can compare sculpt in VR (top) vs. finished product (bottom).


My process has been consistent so far though. Initial concept in pen and paper, revision in photoshop. Start sculpt in Adobe Medium, bring sculpt into Maya to fix transform, then onto Topogun for retopology. Export from Topogun back into Maya to rename, create simple UVs. Then onto Houdini for more complex auto UVs. After Houdini, character goes into Zbrush for details and high poly pass. High poly and low poly are exported back again to Maya for renaming and for UVs sanity checks. Then to Substance Painter for baking maps and painting textures. Finally to Marmoset Toolbag for rendering. All in all the character ends up going through eight different applications in one way or another.



Onto rigging/math/scripting. Last week's parent matrix constraint did not account for joint orient values. This week's parent matrix constraint does account for joint orient values. Woo, progress! Thanks to Jarred Love for his insight.


import pymel.core as pm
        
def parentMatrixConstraint(driver=None, target=None, t=True, r=True, s=True, offset=False, joint_orient=False):
    """
    Creates a parent matrix constraint between given driver and target. Could use selected objects too.

    Shout-out to Jarred Love for his tutorials.

    Args:
        driver (pm.nodetypes.Transform): Transform that will drive the given target

        target (pm.nodetypes.Transform): Transform that will be driven by given driver.

        t (boolean): If True, will connect translate channel to be driven.

        r (boolean): If True, will connect rotate channel to be driven.

        s (boolean): If True, will connect scale channel to be driven.

        offset (boolean): If True, will maintain current transform relation between given driver and target.

        joint_orient (boolean): If True, AND given target transform has non-zero joint orient values,
        will create extra nodes to account for such values. Else will set joint orient values to zero.
    """
    if not driver or not target:
        selected = pm.selected()

        if len(selected) < 2:
            pm.error('Not enough items selected and no driver or target found!')

        driver = selected[-2]
        target = selected[-1]

    name = target.nodeName()
    matrix_multiplication = pm.createNode('multMatrix', n=name + pcfg.parent_matrix_mult_suffix)
    decompose_matrix = pm.createNode('decomposeMatrix', n=name + pcfg.parent_matrix_decomp_suffix)

    if offset:
        offset = target.worldMatrix.get() * driver.worldInverseMatrix.get()
        matrix_multiplication.matrixIn[0].set(offset)
        driver.worldMatrix[0] >> matrix_multiplication.matrixIn[1]
        target.parentInverseMatrix[0] >> matrix_multiplication.matrixIn[2]
    else:
        driver.worldMatrix[0] >> matrix_multiplication.matrixIn[0]
        target.parentInverseMatrix[0] >> matrix_multiplication.matrixIn[1]

    matrix_multiplication.matrixSum >> decompose_matrix.inputMatrix

    if t:
        decompose_matrix.outputTranslate >> target.translate

    if r:
        if target.hasAttr('jointOrient') and target.jointOrient.get() != pm.dt.Vector(0, 0, 0):
            if joint_orient:
                compose_matrix = pm.createNode('composeMatrix', n=name + pcfg.parent_matrix_rot_comp_suffix)
                compose_matrix.inputRotate.set(target.jointOrient.get())
                parent = target.getParent()

                if parent:
                    mult_rot_matrix = pm.createNode('multMatrix', n=name + pcfg.parent_matrix_rot_mult_suffix)
                    compose_matrix.outputMatrix >> mult_rot_matrix.matrixIn[0]
                    parent.worldMatrix >> mult_rot_matrix.matrixIn[1]
                    joint_orient_matrix_output = mult_rot_matrix.matrixSum
                else:
                    joint_orient_matrix_output = compose_matrix.outputMatrix

                inverse_matrix = pm.createNode('inverseMatrix', n=name + pcfg.parent_matrix_rot_inv_suffix)
                joint_orient_matrix_output >> inverse_matrix.inputMatrix

                mult_rot_matrix = pm.createNode('multMatrix', n=name + pcfg.parent_matrix_rot_mult_suffix)

                if offset:
                    offset = target.worldMatrix.get() * driver.worldInverseMatrix.get()
                    mult_rot_matrix.matrixIn[0].set(offset)
                    driver.worldMatrix >> mult_rot_matrix.matrixIn[1]
                    inverse_matrix.outputMatrix >> mult_rot_matrix.matrixIn[2]
                else:
                    driver.worldMatrix >> mult_rot_matrix.matrixIn[0]
                    inverse_matrix.outputMatrix >> mult_rot_matrix.matrixIn[1]

                rotate_decompose = pm.createNode('decomposeMatrix', n=name + pcfg.parent_matrix_rot_decomp_suffix)
                mult_rot_matrix.matrixSum >> rotate_decompose.inputMatrix
                rotate_decompose.outputRotate >> target.rotate

            else:
                target.jointOrient.set((0, 0, 0))
                decompose_matrix.outputRotate >> target.rotate

        else:
            decompose_matrix.outputRotate >> target.rotate

    if s:
        decompose_matrix.outputScale >> target.scale