STEP BY STEP: Master ma­te­rial cre­ation in Light­wave

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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.

02

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.

03

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.

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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.

06

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.

08

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.

09

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.

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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

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