STEP BY STEP: Master material creation in Lightwave
Andrew Comb teaches you to get to grips with metals
Wbeen ith the 2018 version of Lightwave, there has
a huge paradigm shift in surfacing and lighting, leaving a lot of users scratching their heads. The principled material is now the new default material (replacing the ageing standard material). It looks foreboding, but it’s a lot less complicated than it looks at first glance. There are some other materials for specific uses, but for most materials you require the Principled BSDF should suffice.
The first thing to understand is it works like a set of nested materials, with linked properties, with a specific order of overriding and layering. At the base of the stack is an insulator material, useful for opaque, diffuse materials, such as wood, plastic, paint. Next up is the subsurface scattering, which replaces the diffuse component, for making waxy or translucent materials. Next is transparency, which replaces the previous two, for creating glass and transparent plastics, and lastly, metallic, which makes the material into metals. All of the sub-materials share bump, normal, roughness and anisotropy setting. Beyond that, there’s a sheen value, if you’re trying to create velvet fabrics, and a special thin mode, with translucency, if you’re doing leaves or paper. Finally there’s a clear-coat which layers above them all, with its own glossiness setting. The design is meant to be artist friendly, with most of the properties represented with a 0-100 per cent value, to work with greyscale textures, so that an artist can paint the amount they want in texturing software. In most cases what you don’t need to do is any complex node setups, just layered textures.
Mostly, for hard surfaces, you will only need to use three values – roughness, colour and metallic. You will find hundreds of online resources, or painting tools, for ‘PBR textures’ and they will usually contain only these, and a normal or bump map.
These are your main texture resources, and then after that you only need to tweak the values to taste, or blend with other texture sets, using masks.
I will show how I created a brushed metal anisotropic material, by layering textures, for my sci-fi door, giving you some of the basics in using the node editor and the new PBSDF material.
01 Four materials in one Here we are showing the four main material modes in the PBSDF, an insulator, SSS, Transparent and Metal surface. They are the same
colour and roughness settings, but four very different looks. In the case of metals, which I am showing here, the only settings you need are colour, for the metal colour, roughness and the amount of metallic, which can be set in the material or piped in as textures in the node editor.
Opengl Settings While Opengl can’t show everything, it’s worth turning everything on in the display settings, so you can see normal map textures, roughness and depictions of the lights, in the display port. Note, that the new display mode only shows the texture plugged directly into the material, not further down your node tree.
Basic rough metal Making a basic rough brushed metal is quite a simple process with a few repeating textures. Here I apply the metallic, roughness and normal texture to the object. I applied it using the image node into the named inputs. Here I dropped the opacity of the roughness to taste and set the mapping type to Cubic for simplicity. The brushed effect of the texture roughness and normal map work effectively but we can push this further. I also use a Maths> vector> multiply node to mix the surface colour with an occlusion, to give a subtle wear look in the recesses.
04 Mix up textures To vary the metal up, I mix in a second, slightly different scuffed texture – the effect is very subtle, but it gives an extra layer of natural patina to the roughness effect. In most materials in PBSDF roughness does a lot of the work for you. Setting it to be a slightly different scale to the other texture helps to mask tiling. Just chain the textures as shown and change the opacity so they blend.
Blending modes in the image node work much the same as Photoshop layers. Pre-baked hand painted texture sets are obviously much better, but it’s possible to give very effective results with just blended tiled textures.
Apply projections For metal to have anisotropy the shader needs to know which direction the surface goes and which direction to stretch the specular highlight. For this material, because the texture is cubic mapped I use a cubic mode. Projections can be found in their own area in the node menu. In this case the object is simple, but for more complicated objects you will need a uv map and use a uv projection. On the surface you will need to set how much anisotropy you want and the angle you want it to be at (both of which can be textured also). By default at rotation 0 the stretching goes along the V direction and in this case my texture has horizontal (u) ‘grain’, so I left it as the default option, the slider works as a 180 degree value, so if you needed to rotate it 90 degrees, the value would be 50 per cent.
Vary metal types To make the door look like it’s made of a few different kinds of metal I created a few different materials, which have different material properties. By varying the mix of the strength of the textures, and the amount of anisotropy and colour it gives the appearance of a subtly different metal. You can of course paint this as a single texture set in a painting application like Substance Painter.
07 UV map the object To do the more complex mapping of the radial texture, you need to properly uv map the object. In this case it’s a simple planar projection, in the Z axis (the door is modelled in X-Y). A new feature in Lightwave 2018, is default uv, which can be set in the uv tool, or the Vertex map editor, this will then automatically be the projection for any given material and can be used in textures too.
Create the radial textures To make a brushed metal texture I did a simple noise texture in Photoshop and then applied a radial blur to make it spin like a spun brushed surface. And for the rotation texture it was just a radial gradient from black to white.
While I did these in Photoshop, most basic image editors can do these functions. I provided these with Filesilo in case you don’t have a suitable image editor.
Mix the textures together using the same scuffed texture mixed with the radial noise texture, I turned it down to just 10 per cent as sometimes less is more with these effects. The noise which causes anisotropy is meant to be microscopic so it shouldn’t be too visible but that’s to taste. Similarly I dial back the normal texture as it’s meant to be subtle. The texture for Anisotropic rotation is multiplied by two. As I mentioned earlier, 100 per cent rotates 180 degrees, but in this case we need it to be a full 360 degree spin, so it distorts the stretching effect, to match the other textures. As previously mentioned, because we have a default uv applied, there’s no reason to assign a uv projection.
Colourspaces As a final note, when importing textures make sure to set all images which are not being used for colouration to Linear which is effectively disabling the CS settings for that image. Normal maps especially should never be colour corrected, as their colour values are to control normal direction, so changing them will upset your normal. Any colour textures should of course be colour managed, and set to the default SRGB, to match SRGB displays correctly.
Andrew Comb andrewcomb.com bio Freelance 3D artist and tutorial creator. Specialist in PBR lighting, texturing and modelling