USE MAR­MOSET FOR VR PRE­SEN­TA­TION

Free­lance il­lus­tra­tor Martin Ne­be­long demon­strates how to present VR models ef­fi­ciently in Mar­moset

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Mar­moset Tool­bag is by no means new to the 3D in­dus­try. It’s been out for years, and it’s known for its ro­bust­ness and ease of use, es­pe­cially when it comes to show­ing off game as­sets and smaller, con­fined projects.

Ba­si­cally, Mar­moset Tool­bag is a live viewer that gives you in­stant feed­back when you change lights, ma­te­ri­als and so on. For me as an artist who’s used to mak­ing brush marks on pa­per or in Pho­to­shop and in­stantly see­ing the re­sult, hav­ing to wait for ren­der­ers to fin­ish to see the tweaks I made to my scene has al­ways been a sure­fire way of get­ting me out of the creative flow.

I’ve used Mar­moset Tool­bag for many years, but only af­ter I started work­ing with VR mod­el­ling and paint­ing have I come to re­alise just how pow­er­ful a tool it can be. It has its lim­i­ta­tions, and it’s not good in all sce­nar­ios, but what it does, it does re­ally fast and re­ally well. Turns out it’s the per­fect com­pan­ion for VR sculpt­ing and draw­ing.

In this tu­to­rial, I’ll talk about how I use Mar­moset Tool­bag with con­tent made in VR. I use mostly four VR pro­grams: Quill, An­imvr, Ocu­lus Medium and Master­piecevr. All of them can out­put models with ver­tex colours that we can then use in Mar­moset.

By us­ing ver­tex colours, you’ll be able to com­pletely skip the nor­mal UV un­wrap­ping and tex­tur­ing work­flow, which will save you pre­cious time.

01 PRE­PARE con­tent

From An­imvr, go to the Save tab and se­lect Ex­port as FBX. From Quill, go to the Save tab and save as FBX. At the mo­ment, an­i­ma­tion ex­ported from Quill and An­imvr doesn’t work right in Mar­moset Tool­bag, so de­s­e­lect Ex­port An­i­ma­tion if you have an­i­ma­tion in your file. Make sure that your scene is aligned to the scene grid, as that way your model should align cor­rectly in Mar­moset Tool­bag.

02 Ba­sics of Mar­moset

The most im­por­tant el­e­ments are lights, cam­era set­tings and ren­der­ing set­tings. We’ll talk about each el­e­ment in de­tail as we need them. Mar­moset uses a hi­er­ar­chy of el­e­ments which lets you, for ex­am­ple, drag a light source un­der a cam­era to make it a ‘child’ of it.

03 Quill and an­imvr

The first models we’ll be set­ting up are from Quill, but the prin­ci­ple is the same with An­imvr. Both pro­grams en­able you to paint in VR, with­out any light sources or ma­te­rial types.

None of the pro­grams have any built-in post-pro­cess­ing fea­tures, and this is where Mar­moset comes in handy. You’ll be able to tweak curves and lev­els, add noise, glow and var­i­ous cam­era ef­fects such as depth of field and dis­tor­tion.

First, we want to get as close to what we saw in VR as pos­si­ble and then work from there.

04 im­port into Mar­moset tool­bag

Press File>im­port Model and lo­cate your file. Hit Im­port. The model should ap­pear in your scene stack. With ob­jects ex­ported from An­imvr and Quill, you’ll most likely have to de­s­e­lect Cull Back Faces. Since most of the time you’re ba­si­cally paint­ing with flat planes in both pro­grams, the back­side of those planes will other­wise ap­pear trans­par­ent. By turn­ing of Cull Back Faces, both sides are vis­i­ble.

05 light your scene

Try­ing to ac­tu­ally light the ge­om­e­try from Quill and An­imvr re­quires a very tight ‘draw­ing’ for it to look good. Due to the na­ture of the pro­grams, a lot of the im­per­fec­tions of the ge­om­e­try they out­put are hid­den by the fact that the sur­faces are un­lit.

Gen­er­ally, hard-sur­face el­e­ments do bet­ter than or­ganic el­e­ments when you try to add lights to your scene. Also, el­e­ments made up of as sim­ple and few strokes as pos­si­ble tend to do well. As soon as you build an el­e­ment that con­sists of a lot of brush strokes, you’ll start to no­tice that it works bet­ter un­lit.

It’s a good idea to play around a bit with the set­tings. One draw­ing might look good lit and with re­flec­tion and glossi­ness en­abled, yet an­other might look ter­ri­ble.

06 un­lit scene

The first ver­sion is the one that will be clos­est to what you saw in VR. To get this re­sult, go to your ma­te­rial and make sure Albedo is set to Ver­tex Color, Dif­fu­sion is set to Un­lit, Mi­cro­sur­face is set to Gloss 0, Re­flec­tiv­ity is set to Spec­u­lar with 0 in­ten­sity and fi­nally Fres­nel is at 0.

If your scene con­tains trans­par­ent el­e­ments, make sure to en­able Ver­tex Al­pha un­der Albedo, and un­der Trans­parency you should set Cutout and use Albedo al­pha. Also, Chan­nel should be set to A.

In our ex­am­ple some post­pro­cess­ing has been ap­plied to add depth of field and to tweak the colours. We’ll get to that later on.

07 light types

For the next two ma­te­rial/ light­ing sce­nar­ios, we need lights. Each light type in Mar­moset has com­mon set­tings and light-spe­cific set­tings. The most im­por­tant light set­tings are: Bright­ness; Dis­tance, which has a big im­pact on the look

of vol­u­met­ric light when us­ing fog; Con­tact Re­fine­ment, which does ex­actly what the name im­plies; and the shape set­tings, which scales the light caster and af­fects the sharp­ness of cast shad­ows. A small light caster gives sharp shad­ows, and a large one gives soft shad­ows.

If you ex­pe­ri­ence blocky shad­ows, go to the ren­der­ing set­tings and up the shadow res­o­lu­tion, or try to en­able the Use Cas­cades op­tion un­der Shad­ows. With very large scenes it might not be pos­si­ble to have sharp shad­ows due to the way Mar­moset cal­cu­lates shad­ows. In those cases spot­lights with a small ra­dius work best, and if that doesn’t help, up the light caster scale to soften the shad­ows.

In the above im­age, in the first ex­am­ple on the left I have a spot­light with a Bright­ness set­ting of 5, a Dis­tance set­ting of 1.3 and a width of 0.3. No­tice how soft the shad­ows ap­pear, and how pro­nounced the vol­u­met­ric light rays are. Jump to the Add Fog sec­tion of the tu­to­rial for more in­for­ma­tion on how to achieve this. The sec­ond ex­am­ple is a di­rec­tional light with a width of 0 which gives very hard shad­ows. The last one is an omni light with a low Dis­tance set­ting, a medium-sized light caster and a fog set to re­act to lights.

We’ll cover HDRI lights in the last part of the tu­to­rial.

08 lit scene

In this ver­sion, we use the same ma­te­rial for the whole scene. Once you get more com­fort­able with Mar­moset, you can make as many in­di­vid­ual ma­te­ri­als as you like and ap­ply those to the dif­fer­ent lay­ers in Quill or An­imvr scenes.

Start off by adding a light to your scene. In my case, I added a spot­light above the house with a an­gle set­ting that’s large enough for the light to il­lu­mi­nate the house and the sur­round­ing gar­den. I can’t see the light at the mo­ment, due to the ‘Un­lit’ prop­erty of my ma­te­rial.

To get the ma­te­rial to re­act to the light source, you should set Albedo to Ver­tex Color, Mi­cro­sur­face to Gloss 0.3, and Hori­zon Smooth­ing to 0. Re­flec­tiv­ity is set to Spec­u­lar with 0.006 in­ten­sity, just to get a small re­flec­tion. Fres­nel is set to 1.

You also need to set Dif­fu­sion to Lam­ber­tian or one of the other tech­niques, de­pend­ing on your ma­te­rial; just don’t set it to Un­lit.

Un­der Ren­der set­tings, en­able Lo­cal Re­flec­tions and En­able GI. I set GI bright­ness to around 4. This ba­si­cally turns all your ob­jects into light cast­ers which will bounce the light around in your scene to give a more real­is­tic re­sult. De­pend­ing on the size of your scene, you might have to up the GI res­o­lu­tion or tweak the Voxel Scene Fit slider.

As you can see, not all el­e­ments look equally good with those set­tings. Par­tic­u­larly the girl and laun­dry suf­fer from a very un­even sur­face. To get us­able re­sults with scenes like this, you’ll have to ex­per­i­ment quite a bit… or you could go to the next step and get the best of both worlds!

09 com­bined

As we saw above, some el­e­ments look good un­lit, while oth­ers ben­e­fit from lights and shadow. So what we can do is com­bine the two tech­niques. This is a bit of a ‘hack’ and won’t work in all sce­nar­ios. For ex­am­ple, you’d ex­pect a char­ac­ter stand­ing in a strong cone of light to cast a shadow. But in this case, since the girl is sit­ting like she is, we don’t need her to cast a shadow.

For most of the el­e­ments in the scene I use the ma­te­rial we cre­ated in the step above, ex­cept for the girl and the laun­dry to which I ap­ply the Un­lit ma­te­rial.

10 have fun!

Now that you have an idea about how ma­te­ri­als and lights work with Quill and An­imvr scenes, it’s time to ex­per­i­ment. In this ver­sion I tried to go for a night-time look, and kept the girl un­lit while ev­ery­thing else is lit. I toned the ver­tex colour of the girl down a bit, by ap­ply­ing a lo­cal colour on top of the ver­tex colour. There’s some pretty ob­vi­ous band­ing go­ing on in the grass plane, but this could eas­ily be painted over in Pho­to­shop for a more fin­ished look. Be­ing able to play around with mood in your VR draw­ings like this is pretty pow­er­ful for look de­vel­op­ment, con­cept art or il­lus­tra­tions in gen­eral.

11 add fog

One of the big­gest chal­lenges with un­lit scenes is to con­vey dis­tance, and at­mo­spher­ics can help with that. To add fog to your scene, click the New Fog but­ton at the top-left cor­ner of the screen. Play with the set­tings to get the look you want. The set­tings un­der Il­lu­mi­na­tion are es­pe­cially im­por­tant if you want a dra­matic god-ray ef­fect. To ac­tu­ally get the rays to show up, you ob­vi­ously need a light source for them to emit from. So make a spot, omni or di­rec­tional light be­hind some of your scene el­e­ments, and tweak away at fog and lights set­tings.

12 PRE­PARE in Medium

This leads us to the sec­ond part of the tu­to­rial, where I’ll talk about how to present scenes from Medium or Master­piecevr in Mar­moset Tool­bag.

From Ocu­lus Medium, ex­port your file as ei­ther OBJ or FBX. OBJ merges all your lay­ers into one, and FBX re­tains lay­ers. De­pend­ing on how large and com­plex your scene is, it might be a good idea to dec­i­mate your model, ei­ther us­ing the built-in dec­i­ma­tion tool in the VR pro­gram, or through pro­grams such as Zbrush or 3D-coat. Gen­er­ally I try to keep the poly­gon count below 10 mil­lion in Mar­moset.

13 PRE­PARE in Master­piecevr

From Master­piecevr, ex­port your file as FBX. Master­piecevr doesn’t sup­port lay­ers per se, but you can draw with poly­gons, a bit like what you do in Quill and An­imvr. These strokes are each ex­ported as a sep­a­rate layer if you ex­port as FBX.

De­pend­ing on the type of scene I’ve done in Master­piecevr, I might take the model into Zbrush to com­bine poly­gon strokes into mean­ing­ful groups, in­stead of hav­ing each stroke be one layer. The model I’ll be set­ting up in the sec­ond part of this tu­to­rial is a quick scene I sculpted in Master­piecevr. Speed is one of the big­gest strengths of VR sculpt­ing and draw­ing, and this scene took a bit less than an hour to sculpt in VR.

Now let’s see what a bit of light and ma­te­ri­als can do!

14 Ba­sic setup

Start out by ro­tat­ing your im­ported scene. I usu­ally make a new shadow catcher ob­ject and ro­tate the model ac­cord­ing to that. You can make nu­meric in­puts in the Trans­form cat­e­gory un­der your im­ported ob­ject if you need more pre­ci­sion. You might also want to scale up or down el­e­ments in your scene. You can switch to trans­form mode by hit­ting Ctrl+r. To get back to move mode, hit Ctrl+t.

15 find a suit­able en­vi­ron­ment

HDRIS in Mar­moset are the last light type we need to cover. You’ll find those un­der the Sky ob­ject in your scene stack. You’re prob­a­bly fa­mil­iar with HDRIS from other 3D pro­grams. They work about the same in Mar­moset Tool­bag, with the added func­tion­al­ity of a ‘light edi­tor’ that al­lows you to click the pre­view of the HDRI im­age, and place ac­tual lights that you can then tweak based on the colours in the HDRI. In the ex­am­ple here you see the dif­fer­ence be­tween just light­ing the scene us­ing the HDRI and then us­ing both HDRI and child lights. I placed a child light di­rectly in the cen­tre of the sun in the HDRI, which gives me cast shad­ows that match the sun place­ment. You can tweak

the child lights by click­ing them un­der­neath the Sky ob­ject. When you ro­tate the HDRI en­vi­ron­ment, the child lights ro­tate too.

16 Ver­tex colour

For this scene I use the ver­tex colour di­rectly from Master­piecevr. This is the same pro­ce­dure as with the Quill scene. Go into the ma­te­rial, choose Ver­tex Color and tweak glossi­ness and re­flec­tion un­til you’re happy with the re­sult.

In the ex­am­ple, I’ve added ver­tex colour to the ‘solid’ part of the Master­piecevr sculpt, leav­ing only the poly­gon strokes un­coloured.

17 fin­ish the Ba­sic Ma­te­ri­als

I do the same for the poly­gon el­e­ments in the scene. At the mo­ment, the scene looks bland and we re­ally need some light. I plan on hav­ing the ban­ners cast coloured lights on the sur­round­ings and ground floor, but for now they’re just their lo­cal colour.

18 let there Be light!

I add a spot­light al­most di­rectly above the scene and tweak the bright­ness and shape un­til I’m happy with the re­sult. I find the spot­light is eas­ier to ma­nip­u­late than di­rec­tional light when us­ing fog and god rays, be­cause of the dis­tance set­ting.

19 sub­sur­face scat­ter­ing

To get the ef­fect of the light shin­ing through the ban­ners, I need to en­able Sub­sur­face Scat­ter in the Dif­fuse set­ting of the ma­te­rial for the ban­ners. Re­mem­ber to turn on En­able GI in the Global Il­lu­mi­na­tion set­tings un­der Ren­der. This will en­able coloured light to pass through the ban­ners and il­lu­mi­nate the ground plane and sur­round­ing build­ings. As you can tell, the dif­fer­ence is night and day!

20 ex­pand the scene

The Master­piecevr sculpt doesn’t cover as much space as I need, so to ex­pand the scene, I duplicate the sculpt and ro­tate it to in­crease the length of the street in a mod­u­lar fash­ion. Gen­er­ally when do­ing sculpts like this, I’ll duplicate el­e­ments and move them around to add vari­a­tion to the scene. You’d be amazed how much you can get by ‘cheat­ing’ like this.

21 ex­tra lights

Fi­nally, I add some ad­di­tional lights in the small shops, and a Fog ob­ject to add at­mos­phere. I tweak the set­tings un­til I find a re­sult I like. No­tice the nice rays of light we get due to the small con­fetti-like ob­jects in the air, and the ban­ners which break the light into smaller rays of light.

22 cam­era set­tings

I added depth of field (you choose your fo­cus point by press­ing the scroll wheel), bar­rel dis­tor­tion to get a fish­eye lens ef­fect, chro­matic aber­ra­tion to sim­u­late a cam­era lens ef­fect, lens flares, and tweaked the colour set­tings by chang­ing Tone Map­ping to Filmic and ad­just­ing the curves, con­trast and sat­u­ra­tion. I also added a vi­gnette ef­fect and some noise to the fi­nal im­age and voila, we’ve reached the end of the tu­to­rial. Feel free to reach out over so­cial me­dia or email if you have ques­tions about the work­flow. •

au­thor Martin ne­be­long Martin is a free­lance artist liv­ing in Den­mark. He has been work­ing as a 2D artist for 15 years, but since he got his VR head­set, 3D is be­com­ing an in­creas­ingly big­ger part of his work. www.art­sta­tion.com/mar­tin­ity

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