Getting / Setting Material Parameter Values During Runtime

Development Programming & Scripting C++
1

I currently have a system set up to change the value of a scalar parameter (opacity) on the first material index when certain conditions are met.



TArray<FMaterialParameterInfo> info;
TArray<FGuid> guids;
float retrieved_value;

GetMaterial(0)->GetAllScalarParameterInfo(info, guids);
GetMaterial(0)->GetScalarParameterValue(info[0], retrieved_value);

float change = 1.0f;
if (retrieved_value - change <= 0.20f)
{
SetScalarParameterValueOnMaterials("Opacity", 0.20f);
}

I want to avoid using dynamic material instances where possible, and this system doesn’t require using dynamic materials. However, it seems pretty wonky. Is there a better way of doing this?

2

You can’t change parameters on anything other than a Dynamic Material Instance at runtime - that’s what they’re there for.

3

That’s odd if that’s really the case, as this code works fine on a material that wasn’t created as a dynamic instance.

4

Only works on editor because in editor runtime your materials are not cooked yet.

On packaged builds you will not be able to reliably apply changes to root materials.

5

yeah exactly. There shouldn’t be any reason to not use a Dynamic Material really, creating them is super straightforward and you can apply one DMI to as many objects as you like.

6

Ahh that does makes sense, thanks for the info!