Hi,

for a Python script, I want the computed value of a shader tree node input.

I can get the value set at the node itself by myInput.Value(), but I need the evaluated output of any tree connected to it as well (if myInput.InNode() is not None).

Is there a way to do that?

Best regards,

   Michael

Hi Michael.

What do you mean by "evaluated output"? What kind of value would that be?

I have the following code:

        scaleNode = NodeByName(previewMat.ShaderTree(), prefix, actor.Name())
        if scaleNode is not None:
            # extract the Preview material's scale and apply it
            xScale *= scaleNode.Inputs()[0].Value()
            yScale *= scaleNode.Inputs()[1].Value()
            zScale *= scaleNode.Inputs()[2].Value()

The nodes look as follows:

The scaleNode.Inputs()[2].Value() method returns 1 (which makes sense), but I want to get the value of 5 of the math_add as well, in order to compute the effective parameter of the node input.

Best regards,

  Michael

I don' think that's possible, since shaders are evaluated at render time only. Many nodes give different results when rendering, so everything containing a texture node, an u- or v- node, an edge blend or a fresnel node will give different results on different pixels of the render. The only cases in which the results can be caclulated are those with simple, nonvariable numbers - and those can easily be entered in the node directly.

What do you exactly want to do with that?

Hi,

what I want to achieve is to combine Bagginsbill's Parmatic with external renderers.

With the OctanePoserPlugin, it is possible to store Octane material information inside a Poser material (it creates extra nodes for that, so it does not impact the Poser shader).

I have written a small script which can modify the scaling of the color, bump and displacement channels, based on additional disconnected nodes.

Now my idea was to feed in information from dials (the Parmatic approach). Parmatic uses a single node type only, so I will still be able to achieve that for that special case, but a general solution which would allow to hook in arbitrary node trees would be preferrable, of cause.

Best regards,

   Michael

Michael - if you are using the Octane plugin, you just need to keyframe animate the color, bump amount, etc in the Poser material, and then when rendering the animation with the Octane plugin, tick the "Recovert materials each frame" checkbox - then the bump amount at that frame will be used to re-build the Octane material.

Paul