i am a complete newbie when it comes to Unreal Engine, but i am a 3D artist with very rich experience in physically based rendering. I am recently starting to explore game engines to review their capability when it comes to photorealistic rendering, and try to push them to their limits.
From rendering engines, i am used to a scheme where there is some base material with some parameters, into which i can then plug textures and various nodes to create shading network. Unreal engine works on very similar scheme, but i failed to find some basic material properties in the base material node. For example, if i unplug all nodes from the physical material node, i get black, but specular material. So my questions are:
Are there any parameters to control appearance of the material in the base node itself? And if so, where can i find them?
OR do i need to always drive all basic material parameters by nodes, like diffuse or specular color?
Which parameter defines that material is specular if there is not any node connected to it? Why is it specular by default?
And i really dislike working with roughness, since it’s just counter-intuitive form of glossiness parameter, so i was looking for some invert node, that would allow me to invert my glossiness shading network to convert it to roughness, but i did not find any. Is there any node that can invert RGB map result?
Are there any parameters to control appearance of the material in the base node itself? And if so, where can i find them?
Unfortunately not. You’d have to hook up constants to the relevant inputs to control these. I personally create a 3-Vector, and use the three colour components on the node to control a different attribute on the shader node. (e.g R = specular contribution, G = roughness, B = emissive multiplier)
Which parameter defines that material is specular if there is not any node connected to it? Why is it specular by default?
No idea why it defaults to a semi-glossy black. I’d rather it went for 100% diffuse by default, but for now you’d have to manually set the specular/metallic to 0.
And i really dislike working with roughness, since it’s just counter-intuitive form of glossiness parameter, so i was looking for some invert node, that would allow me to invert my glossiness shading network to convert it to roughness, but i did not find any. Is there any node that can invert RGB map result?
Hold your O key on your keyboard, and click in the workspace. 'll make you a OneMinus node, which is the same as an invert/reverse.
If you click on your Material node so it is highlighted in orange, there are some options in the details panel on the left specific to that node, however changing the values will require you to use nodes in most cases for what you are looking for.
As mentioned above, nodes are where you will be changing the values for the vast majority of items. When there is no node plugged in, it defaults to 0 (black). is why you will see a black preview. To change the value, you can use a “Constant” node, which will allow you to input a value, as seen in the following example image:
If you use a OneMinus node to invert, you must have sRGB ticked off in your texture’s settings, or else it will not invert properly and it will give you incorrect results. sRGB should always be off for Roughness, Spec and Metallic maps anyway.
