unreal material instance dynamic null,unreal material dynamic null

When using material instance dynamic with code, it is used in such a way that GetDynamic is performed on the image and saved, then the parameter value is retrieved and a cap is inserted. However, when you build, sometimes the material is null and the effect does not appear. What should I do?

If it’s null, it won’t be imported even though the material is imported again after binding the image again.,unreal