3D World

REN­DER A HEAVY CAD CATER­PIL­LAR MODEL

Pre­pare a heavy CAD model

- Down­load your re­sources For all the as­sets you need go to www.bit.ly/vault-240-meg

at the end of 2017, New Com­mu­ni­ca­tion, a creative and mar­ket­ing agency from Kiel in Ger­many, was asked to cre­ate de­tailed im­ages of the largest Cater­pil­lar gen­er­a­tor set – the 16CM43 – for a press re­lease.

The Cater­pil­lar 16CM43 is a heavy-fuel off-shore gen­er­a­tor set that is used for power gen­er­a­tion. The brief set by the client was to use the data pro­vided by them to pro­duce this im­age, so that in the fu­ture, cut-out im­ages or de­tail shots of the gen­er­a­tor would be pos­si­ble.

From the start it was al­ready clear that this would not be an easy task, be­cause the data pro­vided by Cater­pil­lar would be of the high­est qual­ity. So be­fore we could even be­gin, we had to think about a smart and ef­fi­cient soft­ware/hard­ware pro­duc­tion pipe­line to fit ev­ery­thing into Oc­taneren­der, our ren­der­ing so­lu­tion of choice.

Our soft­ware pipe­line started with Rhinoceros 3D, which is mostly used by in­dus­trial de­sign­ers but is also great for con­vert­ing heavy CAD files. It ex­ports a very nice mesh qual­ity and works in a 64-bit en­vi­ron­ment.

We used a brand-new Dell work­sta­tion with 128MB of RAM, pro­vided by the client. It had a sin­gle 1080ti and a small graph­ics card for video out­put.

In this tu­to­rial I will show you how I han­dled the im­mense amount of data pro­vided and crunched it down for ren­der­ing.

01 Gen­eral prepa­ra­tion

Be­fore we be­gan we talked to the client and made it clear that a STEP file would be the best file for­mat for us. This way we had full con­trol over ex­port­ing into the de­sired file for­mat: FBX. When you can, it’s bet­ter to do the ex­port your­self rather than the client.

02 ref­er­ence im­ages

The client pro­vided us with many ref­er­ence im­ages from real-world gen­er­a­tor sets. These pho­tos were taken by Cater­pil­lar en­gi­neers. This was great be­cause self-taken pho­tos are mostly bet­ter than any­thing you will find on a Google search. They are high-res and give you a good ref­er­ence on even the small­est parts.

03 rhinoceros 3D/ DATA con­ver­sion

It took some time to open up the STEP file, but Rhino did so with­out prob­lems. Even if it’s prefer­able to nav­i­gate and fly around in the view­port, I sug­gest not to do it, as it can cause freez­ing. So just open the file, leave it as it is and se­lect all (Cmd+a), go to the File menu and ex­port se­lected. You can check the Layer tab and if there are lay­ers, you may ex­port sin­gle lay­ers. In my case there weren't, so I had to ex­port ev­ery­thing in one file.

04 DATA prep in cinema 4D: con­sid­er­a­tions

Rhino ex­ported in ten hours which was re­trace­able by the time the file was writ­ten on the sys­tem. So we had our nicely ex­ported FBX file, which had grown to a size of 3.75 gi­ga­bytes. Luck­ily it was un­der 4 gigs, be­cause that is the max size for FBX at the mo­ment.

Af­ter a few min­utes, check­ing RAM con­sump­tion as well, Cinema 4D opened the file. So I first saved a *.C4D file out of it be­fore do­ing any­thing else. Af­ter sav­ing the C4D I recog­nised that the Cinema 4D file was grow­ing to an im­mense 8 gigs. The first thing you can do is delete all UV tags to get the file al­most 50 per cent smaller.

05 or­gan­i­sa­tion

So how could I prep the file if I was not able to see any­thing? I de­cided to go for a sim­ple but ef­fec­tive way of cut­ting out a spe­cific amount of ob­jects and pasting them into a new blank scene. This worked very well as Rhino ex­ported ev­ery­thing or­derly so that ob­jects in a row were parts of a sin­gle gen­eral part.

The main chal­lenge was to fig­ure out how many ob­jects to cut out. I tried dif­fer­ent ob­ject counts, and fur­ther in the project I was lucky to hit al­most the cor­rect num­ber of ob­jects that be­longed to­gether. Ob­jects that did not be­long to one part were sep­a­rated as null ob­jects.

06 cinema 4D helpers

So af­ter fig­ur­ing out how to merge down this many ob­jects I had to think a bit fur­ther. Keep­ing

check your specs Be sure to have enough RAM in your ma­chine when you work with heavy CAD files.

in mind that we wanted to use Oc­tane Ren­der, know­ing the VRAM of the graph­ics card is the crux of the mat­ter. So I had to use a good bunch of Cinema 4D's Cloning Sys­tem and other small helpers that crunch the file down to a size that fits into the VRAM. There are many op­tions to help you with this, like ar­rays, in­stances, xrefs and of course Mo­graph Clones.

07 work with Xrefs

For the heav­i­est parts (re­fer­ring to the poly­gon count of the ob­ject) I de­cided to use the xref sys­tem of Cinema 4D. Sin­gle ob­jects were saved as new C4D files and then could be loaded as an xref into the main scene. Your scene per­forms quite a bit faster when you have heavy ge­om­e­try ex­cluded into an xref file. You can work on it in the ex­cluded file and hit re­fresh on the xref to up­date your ob­ject.

08 use The r19 poly­gon re­duc­tion Fea­ture

A freshly new fea­ture in R19 was the poly­gon re­ducer, which came in very handy! This works even with com­plex CAD ge­om­e­try. Sim­ply use it like a mod­i­fier ob­ject and af­ter some cal­cu­la­tion time you can see the re­sult. So for some ob­jects that had quite a large amount of poly­gons I made a lower ver­sion of some parts, just like a level of

Try it out first You can use a fully func­tional ver­sion of Rhinoceros 3D as a 90day trial, if you’d like to test out its fea­tures.

real-world scale Al­ways work with cor­rect real-world sizes in your scene. It’s help­ful when set­ting up cam­era and lights as well.

de­tail. The re­duced parts were used if the cam­era was some dis­tance away from the ob­ject.

09 Ar­rays

When you have ob­jects that are aligned in a ring-like pat­tern, ar­rays will come in handy. You can even check Ren­der In­stances to get more per­for­mance. I like ar­rays a lot, as I find that they per­form very well. Just put the de­sired ob­ject in the ar­ray and with the help of the pa­ram­e­ters you can ad­just al­most ev­ery­thing you need.

10 Mo­graph clon­ers AND in­stances

One of the most pow­er­ful in­stanc­ing sys­tems within Cinema 4D is Mo­graph and Mo­graph clones. This is the fea­ture I used most of the time. Ev­ery time a sin­gle ob­ject re­peats it­self a spe­cific amount of times, use Mo­graph. So for ex­am­ple I used it for cloning the cylin­der heads, ev­ery­thing that’s un­der­neath, or screws that were aligned on the out­side. You can even gen­er­ate an in­stance out of a cloned ob­ject, or use it in a sym­me­try ob­ject. Some­times it’s even use­ful to merge down a large num­ber of ob­jects.

11 ren­der in­stances AND oc­taneren­der

When you are us­ing mul­ti­ple clones in­side of Cloner, be care­ful. Some­how Oc­tane re­fuses to ren­der these cloned clones when they are checked as Ren­der In­stances. Be sure to look af­ter that be­fore ren­der­ing. Other en­gines like V-ray, Corona or the de­fault C4D Ren­der will ren­der it any­way.

12 or­gan­ise your scene

Be sure to have a good, ef­fi­cient method for or­gan­is­ing your scene. You will avoid trou­ble when you have a nice and clean struc­ture. For ex­am­ple, you can use lay­ers or null ob­jects to get ev­ery­thing or­gan­ised. When you have in­for­ma­tion from the client, it’s nice to name ev­ery­thing cor­rectly too. You can use ‘Icon Color’ for null ob­jects to split ev­ery­thing fur­ther in the ob­ject man­ager.

13 Delete Faces Man­u­ally

On very com­plex ge­om­e­try where the poly­gon re­ducer re­fused to work, I man­u­ally deleted poly­gons that would not be vis­i­ble – ba­si­cally ev­ery­thing that’s in­side and hence not im­por­tant for a hero shot. When you delete faces, Cinema 4D will leave the ver­tex points, so be sure to op­ti­mise your scene and check ‘Delete Un­used Points’ and you are ready to go. Be sure that you leave the orig­i­nal ge­om­e­try as a sin­gle saved file for a backup.

14 set up scene/ cam­era po­si­tion

For these im­ages I used a pretty long fo­cal dis­tance to avoid dis­tor­tions from the cam­era lens. A nice ad­di­tional way to get rid of these is hid­den in the Oc­tane cam­era tag: Per­spec­tive Cor­rec­tion.

15 Model weld­ing seams

For some parts it was nec­es­sary to model weld­ing seams. There are two ways to do this: mod­el­ling, or with a weld dis­place map. I de­cided to go for mod­el­ling be­cause it’s faster.

In my case I needed a ring-like weld seam. So, sim­ply use a ring ob­ject. Con­vert it to an ed­itable Poly­gon, go to Point mode and se­lect all Points. Use the ‘Set point value’ com­mand in the At­tribute win­dow, choose ‘Crum­ple(ax­ial)’ from the menu and try some val­ues un­til you get your de­sired look.

16 Ad­di­tional helpers

If you barely have time to fin­ish your work and there is an in­creas­ing work­load, you can cheat a lit­tle on mod­el­ling when you sim­ply use tex­tures with bumps and nor­mals. There are a lot of free tools on the mar­ket that are good for these pur­poses.

For ex­am­ple, Crazy­bump. I used this for an ana­log In­ter­face with some but­tons and some scale in­di­ca­tors as seen in the screen­shot.

17 clay ren­der­ing

When your model is set up in the way you want it, it’s al­ways nice to do some ren­der­ings in clay ‘mode’. It’s also a way to test if Oc­tane ren­ders it out or if there are any me­mory is­sues. So this is a smart method to test your scene and to have some first im­ages for your client that look bet­ter than some Opengl screen­shots.

You can use the day­light sys­tem with a sun or an HDRI en­vi­ron­ment, or sim­ply use the de­fault back­ground colour from Oc­tane and hit ren­der.

18 shade in oc­tane For A heat-ex­posed look

For tex­tur­ing/shad­ing I used the ref­er­ence im­ages that were pro­vided to build up some shaders. Mostly it was straight­for­ward. Use cor­rect IOR val­ues when you do glossy ma­te­ri­als. To break it up a bit I made a shader that looks like some parts were threaded with heat. It’s easy to do with Oc­tane Dirt in in­verse mode and a ramp with some nice colours to make it look like it was ex­posed to great heat.

19 light­ing in oc­tane

I de­cided to light it man­u­ally rather than us­ing an HDRI or us­ing HDRI Stu­dio, which is a great tool by the way. I placed Area lights around the en­gine and used smaller Area lights to lighten up spe­cific points of in­ter­est. You can uncheck ‘Vis­i­ble for Spec­u­lar’ in the light op­tions when you just want it for the dif­fuse or the other way. I also mixed some light colours to make it a bit more in­ter­est­ing. You can use the Kelvin slider in the light op­tions for the Oc­tane Light to do this.

20 ren­der set­tings in oc­tane

Ba­si­cally Oc­tane's ren­der set­tings are not that com­pli­cated; there’s not that much you can do wrong. I use the path tracer al­most ev­ery time as my main ren­der ker­nel. Be sure to have enough sam­ples es­pe­cially when you are work­ing with depth of field. There­fore, here we need some more sam­ples and it may even take a while un­til it’s free of noise.

When you have fire­flies or hotspots in your ren­der­ing, use the GI Clamp slider and lower it down un­til they dis­ap­pear. In the Oc­tane tab in the main ren­der set­tings en­able Ren­der Passes and choose your lay­ers for later post­pro­duc­tion. Use 16 or 32-bit im­ages when you are sav­ing your im­age.

21 post-pro­duc­tion

With the ren­dered multi-pass im­age I did some mi­nor colour cor­rec­tions in Pho­to­shop. As al­ways

I used a slight amount of Am­bi­ent Oc­clu­sion with a mul­ti­ply around 10-20%. Don’t use more, it will look un­nat­u­ral and dirty. With the ma­te­rial ID and the Pho­to­shop colour se­lec­tion I was able to do a quick se­lec­tion of parts that needed a bit more tweak­ing. Use the se­lec­tion to cre­ate masks and colour cor­rect in a non-de­struc­tive way. With the lay­ers in­cluded in your multi-layer im­age you can sim­ply ad­just the opac­ity, for ex­am­ple, for more re­flec­tion. For the ground shadow I used Cinema 4D's de­fault ren­der Am­bi­ent Oc­clu­sion be­cause I like it more than the Oc­tane Oc­clu­sion pass.

22 proof Fi­nal re­sults

One of the main tasks was to get as close as pos­si­ble to the typ­i­cal Cater­pil­lar yel­low, even in print! So we used our Print Proofer here at New Com­mu­ni­ca­tion to get as close as we could. We needed sev­eral at­tempts to get the de­sired re­sult. If you have re­flec­tive ma­te­ri­als on your ren­der it’s not easy to grade the colours to the ref­er­ence. So my ad­vice is to look for a re­gion on your ren­der where there’s al­most no re­flec­tion go­ing on, no shad­ows and no self shad­ow­ing. It’s the best place to do the grad­ing. We used Pho­to­shop to do the job but you can do it in other post-pro­duc­tion soft­ware as well.

 ??  ??
 ??  ??
 ??  ??
 ??  ?? Au­thor Michael Tsch­ern­ja­jew Michael works for New Com­mu­ni­ca­tion, a lead­ing creative agency in Ger­many. new-com­mu­ni­ca­tion. de
Au­thor Michael Tsch­ern­ja­jew Michael works for New Com­mu­ni­ca­tion, a lead­ing creative agency in Ger­many. new-com­mu­ni­ca­tion. de
 ??  ?? 01 & 04
01 & 04
 ??  ?? 03
03
 ??  ?? 02
02
 ??  ?? 05
05
 ??  ?? 06
06
 ??  ?? 07
07
 ??  ?? 10a
10a
 ??  ?? 09
09
 ??  ?? 10b
10b
 ??  ?? 08
08
 ??  ??
 ??  ??
 ??  ?? 12
12
 ??  ?? 15a
15a
 ??  ?? 15b
15b
 ??  ?? 13
13
 ??  ?? 17
17
 ??  ?? 19
19
 ??  ?? 16
16
 ??  ?? 18b
18b
 ??  ?? 18a
18a
 ??  ?? 22
22
 ??  ?? 21
21
 ??  ?? 20
20
 ??  ??
 ??  ??

Newspapers in English

Newspapers from Australia