Override material instance parameters

[jiamingfeng]

Is there anyway to do with the current python binding?

I would like to do something like this:

myMaterialInstance.OverrideScalarParameterDefault("UseThisColor", 1.0, True)

Cheers,
Eric

[jiamingfeng]

As UMaterialInstanceConstant doesn't change parameters at Runtime, I have to wrap the following functions in my own UEPyMaterialInstance.h/.cpp

SetScalarParameterValueEditorOnly();
SetVectorParameterValueEditorOnly();
SetTextureParameterValueEditorOnly();
SetParentEditorOnly();
PostEditChange();

And it all works fine. I can easily create different variation of a material with a script.

@rdeioris, what is the contribution policy here? Possible to push my changes to a dev branch?

[rdeioris]

Yes, the material interface is not exposed to the reflection system (except for very few cases).

I think a UEPyMaterial.c/.cpp api would be a better naming choise, so we can expose all of the material related features (starting from here: https://docs.unrealengine.com/latest/INT/API/Runtime/Engine/Materials/UMaterialInterface/index.html)

Regarding contribution, simply make a pull request for the master branch (add your credits into the CONTRIBUTORS file)

Regarding

SetParentEditorOnly();
PostEditChange();

combine them in a single function as PostEditChange() is mandatory.

[jiamingfeng]

Ok, I can call PostEditChange() right after SetParentEditorOnly(). The following functions require to call PostEditChange to populate the changes down the chain as well.

SetScalarParameterValueEditorOnly();
SetVectorParameterValueEditorOnly();
SetTextureParameterValueEditorOnly();

As you may want to set multiple parameters without triggering post edit change event for performance reason, PostEditChange() could be exposed separately.

[rdeioris]

Ok, at this point i think it is better to expose PostEditChange as a generic UObject method and follow the C++ pattern by calling it manually.

[jiamingfeng]

I didn't realized that PostEditChange is UObject method. Good call.

[rdeioris]

Remember to make a pull request when your code is usable :) Thanks