Cre­ate and shade re­al­is­tic hon­ey­combs

Dis­cover this sim­ple and log­i­cal ap­proach for cre­at­ing and shad­ing re­al­is­tic hon­ey­combs us­ing vol­umes and sub­sur­face scat­ter­ing ma­te­ri­als

3D World - - CONTENTS - matthew no­vak Matthew No­vak has worked across many dis­ci­plines in­clud­ing mod­el­ling, tex­tur­ing/shad­ing, FX and light­ing, and is cur­rently a lead 3D gen­er­al­ist at Scan­line VFX in Van­cou­ver, Canada. no­

Pro­duce a hon­ey­comb ren­der ooz­ing with de­tail with this step-by-step guide from Matthew No­vak

as a more tech­ni­cal artist I’m al­ways amazed at how de­tailed and in­tri­cate such sim­ple ob­jects and ma­te­ri­als can be. The bark on a tree, the rocks on the ground, even the clouds in the sky con­tain in­sane amounts of de­tail in their shap­ing and form. The way light scat­ters across such sim­ple sur­faces, re­veal­ing so many fine de­tails, is re­ally quite as­tound­ing.

When it comes to shad­ing and de­tail­ing highly com­plex sur­faces the un­der­ly­ing shape/model of the ob­ject plays a large role in the re­sult, es­pe­cially if that ob­ject is translu­cent or re­frac­tive in any way. Light­ing and shad­ing work to­gether in a uni­fied way, and when sur­faces are re­frac­tive or scat­ter light, small im­per­fec­tions and de­tails on the sur­face play a large role in distribut­ing that light fur­ther into the shapes/ob­ject.

With­out get­ting caught up in the small de­tails and try­ing to make things look pixel per­fect, a more or­ganic and free-form pro­ce­dural ap­proach can be taken in the cre­ation of these hon­ey­combs, leav­ing any im­per­fec­tions be­hind. By us­ing vol­umes and pro­ce­du­rals we are able to add many de­tails that would oth­er­wise be very time­con­sum­ing and chal­leng­ing to model by hand, but that add to the re­al­ism of the fi­nal ren­der.

Over the next few pages I hope to in­tro­duce some new tech­niques and meth­ods that you will find use­ful in your own projects.

01 re­search AND un­der­stand your Goal

The key thing to re­mem­ber when start­ing any as­set or the shad­ing/ tex­tur­ing of an as­set is to have a clear vi­sion of the re­sult and its pur­pose. This will de­ter­mine whether you will have to fo­cus on macro (large) de­tails or mi­cro (small) de­tails. In this case we will be mak­ing a hon­ey­comb, which is al­ready a small and in­tri­cate ob­ject. Our goal is to fo­cus on the mi­cro (small) de­tails; to do this we must en­sure that all edges look or­ganic, and that the light falls across the sur­face and scat­ters into it nat­u­rally to re­veal de­tails and shap­ing.

02 cre­ate the Hon­ey­comb Pat­tern

We will start off by open­ing up Maya and mak­ing a sim­ple pat­tern as shown. By hav­ing a sim­ple tileable ge­om­e­try we can du­pli­cate it into al­most any shape we need. You can even use MASH in Maya to cre­ate more com­plex shapes, or you can sim­ply just du­pli­cate the pat­tern by hand. The ge­om­e­try is kept sim­ple for now, as thick­ness and de­tails can be added later.

03 ADD DEPTH to the Hon­ey­combs

Once the pat­tern has been cre­ated we can com­bine the ge­om­e­try, weld the edges and ex­trude. There is no need to be picky about ge­om­e­try here; it will be fully re-cre­ated through vol­umes which are quite for­giv­ing, so even for highly com­plex shapes you can be as messy as you want at this point. Just make sure the re­sult­ing shape is com­bined ge­om­e­try.

04 use Vol­umes to remesh Ge­om­e­try

Un­der the FX tab you can cre­ate a 3D fluid con­tainer; delete the emit­ter. Scale the con­tainer to fit tightly around your hon­ey­comb ge­om­e­try. Select the fluid con­tainer, then select the ob­ject and emit flu­ids from our hon­ey­combs. To pre­vent the flu­ids from mov­ing, we change the fluid con­tainer’s Con­tents Method Ve­loc­ity to Off (zero). Change the fluid con­tainer’s base res­o­lu­tion to a higher num­ber in or­der to have enough vox­els to prop­erly repli­cate the de­tail/ shape of our ob­ject. This way we get an or­ganic look with­out sculpt­ing.

05 De­fine Pro­ce­dural De­tails with Vol­umes

Now we can start to add de­tails. We can ad­just the falloff/sharp­ness un­der the fluid con­tainer on the opac­ity graph un­der the Shad­ing drop­down. Pro­ce­dural de­tails can be added to the sur­face by go­ing to the Tex­tures drop­down and check­ing Tex­ture Opac­ity. Here you can add de­tails us­ing pro­ce­du­rals to add/sub­tract from the fluid/vol­umes. Make sure your view­port tex­tur­ing pre­view is en­abled. To view the vol­ume as a mesh, go to the Sur­face drop­down and set it to sur­face ren­der.

06 mesh the Hon­ey­comb

Make sure you save be­fore this step. To con­vert the fluid/vol­ume into ge­om­e­try select the fluid con­tainer and go to the Mod­ify drop­down in the top menu, then and click Con­vert>fluid to Poly­gons. By de­fault the con­ver­sion will gen­er­ate a tri­an­gu­lated mesh, but this can be changed on the fluid con­tainer un­der out­put along with the mesh res­o­lu­tion/den­sity.

07 ADD Honey with Vol­umes

To cre­ate honey we will gen­er­ate a lower-qual­ity ver­sion by re­peat­ing the pre­vi­ous step and set­ting a low mesh res­o­lu­tion in the out­put set­tings. Cre­ate a 3D fluid con­tainer and emit flu­ids from the low-qual hon­ey­comb, but once it builds up pause your time­bar. Select the fluid con­tainer and in the FX menu un­der Field/solvers set Ini­tial State as the start­ing point of the vol­ume.

08 sim­u­late the Honey

Now we have a good start­ing point where the hon­ey­comb is cov­ered in this new fluid we cre­ated. We can go into the fluid con­tainer and turn the ve­loc­ity back to dy­namic, and in the Con­tent De­tails drop­down un­der Den­sity set the Buoy­ancy to -1. This will cause the flu­ids to drip/sink down­wards. To have proper in­ter­ac­tion be­tween the fluid and the hon­ey­comb mesh, you can also cre­ate a blocker mesh and select the fluid, then the hon­ey­comb mesh, and go to Flu­ids Make Col­lide in the FX menu.

09 mesh the Honey

This step is al­most the same as mesh­ing the hon­ey­comb, ex­cept I would of­ten rec­om­mend aim­ing for a slightly lower qual­ity and see if smooth­ing the shape after re­sults in a more nat­u­ral-look­ing re­sult. The cre­ation of the honey does not have to be done all in one go, so feel free to do this process mul­ti­ple times to add lay­ers of honey or smaller drips and more de­tailed ar­eas.

10 ADD ex­tra De­tails

The hon­ey­comb en­trances should have a nice glaze over them or have the ef­fect as if they are filled with honey. To do this we will model a sim­ple cap, or ex­tract it from our hon­ey­comb pat­tern, and just place these caps over some of the tops of the hon­ey­combs. This will add some breakup to the ren­der and will look as if some of the hon­ey­combs are filled with liq­uid/honey.

11 cre­ate the wax shader

The wax is the main part that the hon­ey­comb is made up of. Since it is sim­i­lar to can­dle wax, light will scat­ter into its sur­face. To achieve this look we will need to use an SSS (Sub­sur­face Scat­ter­ing) ma­te­rial. To keep things more op­ti­mised we will use the Fast SSS shader since it has less pa­ram­e­ters and is quite a bit faster; it is much more suited than a skin shader. We will set the sub­sur­face colour and the scat­ter colour, and not much dif­fuse will be needed as our look is mostly based on the scat­ter­ing ef­fect.

12 cre­ate the wax shader ii

Hon­ey­combs aren’t purely dry wax, and it seems that fur­ther down the wax starts to get more gooey. The top of the hon­ey­comb is more yel­low and dried out, and as it gets deeper we want a more gooey, scat­ter­ing look. To do this we will cre­ate a sec­ondary, more gooey shader, then have the top of the hon­ey­comb use our pre­vi­ous shader and grad­u­ally fade to this more gooey shader at the bot­tom. The key here is to make sure that our shader is re­frac­tive ray­traced.

13 cre­ate the wax shader iii

We have to be able to blend the two shaders to­gether from the tip of the hon­ey­comb to the bot­tom. To do this we will add a V-ray Blend Ma­te­rial with the gooey shader in the base and the dried-out shader in the coat, and put a ramp as the mask with a sim­ple gra­di­ent. This mask will be ap­plied to a UV set that can sim­ply be a pla­nar pro­jec­tion or a pro­jec­tion from the cam­era.

14 make the Honey shader

The honey shader is also a sub­sur­face scat­ter­ing ma­te­rial very sim­i­lar to our gooey shader that we used for the non-waxy part of the hon­ey­comb. A few tweaks can be made to make it look a bit more liq­uidy – these changes can be an ad­just­ment to the in­dex of re­frac­tion, and make sure that you have even more depth on the ray­trace re­frac­tion if you can af­ford longer ren­der times.

15 set up light­ing

For the light­ing I keep the ap­proach as sim­ple as pos­si­ble, as ef­fec­tive light­ing doesn’t come from hav­ing tons of light sources and cheats. Good light­ing is hav­ing as few light sources as needed to ac­com­plish the look with the cor­rect po­si­tion, in­ten­sity and size. The full light­ing setup for this ren­der is an HDRI in a Dome light, and a few sup­port­ing lights with their po­si­tions roughly match­ing the light sources in the HDRI. Us­ing tex­tured lights can also help con­trib­ute to the re­al­ism in some cases.

16 use ipr for fram­ing

IPR mode can help with fram­ing your cam­era and ad­just­ing light­ing. The great thing about IPR mode is that even though it will pro­duce a grainy re­sult, it en­ables you to see a quick over­view of what your fi­nal frame will look like. Even though GI, re­frac­tion and scat­ter­ing are not al­ways shown as ac­cu­rately or ex­actly like they will turn out, it gives a pretty good idea of what the over­all feel will be.

17 fi­nal tweaks AND Ad­just­ments

Once the shad­ing and fram­ing are all com­plete I usu­ally rec­om­mend go­ing through one more round of man­ual ad­just­ments. At this point I look at a pre­view or a low-qual­ity ren­der of my fi­nal im­age and think about what fixes or ad­just­ments would take the least amount of time but have a pos­i­tive im­pact on the fi­nal im­age. I re­ally try to just fo­cus on the big pic­ture and stick to a time­line.

18 DEPTH of field

When it comes to cre­at­ing some­thing that is very small in real-world scale or close to a lens, fo­cus be­comes a huge part of mak­ing some­thing look re­al­is­tic. Of­ten I pre­fer to do this with a Zdepth ren­der pass in com­posit­ing, but in cer­tain cases hav­ing it done in ren­der is worth the per­for­mance hit/ ren­der time in­crease. The key thing to re­mem­ber here is that the larger the aper­ture (lower f-stop) the shal­lower depth of field, and the smaller the aper­ture (higher f-stop) the deeper depth of field.

19 ren­der el­e­ment setup

No mat­ter how sim­ple the ren­der is I al­ways add the ren­der el­e­ments that can pro­vide ex­tra con­trol when com­posit­ing. Even if you don’t plan on do­ing many ad­just­ments I still find it use­ful to have the abil­ity to do so. You should also al­ways be ren­der­ing to EXR or some type of HDR file for­mat, as this way you’re stor­ing as much in­for­ma­tion as pos­si­ble and you will have a greater range of in­for­ma­tion avail­able in your ren­dered im­age.

20 ren­der set­tings

Not only is it im­por­tant that our ren­der looks good, but also that it ren­ders in a rea­son­able amount of time. It gets very tricky when deal­ing with heavy re­frac­tion and SSS, but of­ten by lim­it­ing or low­er­ing the depth of the re­frac­tion and us­ing the Vray Fast SSS we can im­prove ren­der times and also dras­ti­cally change the look of the re­sult. You can also save ren­der time by ren­der­ing slightly more noisy with lower sam­ple rates and re­ly­ing on de­nois­ing to clean up the re­sult.

21 fi­nal im­age At Half res­o­lu­tion

I do my fi­nal ren­der at half res­o­lu­tion and work through one last round of checks. I make any nec­es­sary fi­nal ad­just­ments or cor­rec­tions then ren­der out at full qual­ity set­tings at full res­o­lu­tion. Get­ting into this habit has saved me count­less hours and pre­vents me from ren­der­ing some­thing in su­per high qual­ity only to no­tice some-last minute mis­take I for­got to fix. •

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