Render Explorations

#1

Hi all…
For the past few weeks I’ve been spending time with comparing C4D’s and Messiah’s renderers. You can see the C4D results here. I’ve specficially focused on SSS, HDRI, and GI. I’ve been using TopMod (check out Thomas’ EasyGlass thread) to generate the meshes.

Here are two pieces I completed using Messiah (click images for full versions):

Here are some things I’ve found:

[ul]
[li]I used Photoshop to touch up renders from both apps (mainly fine-tune color balance, apply blurring, and clean up artifacts)[/li][li]C4D seems to handle SSS better overall, although I think Messiah’s results end up looking nicer. The problem I have with Messiah’s SSS is that with complex objects I kept getting hard, black shadows in strange places. I didn’t post an image or scene file but I can if anyone is interested in seeing if they can figure out why.[/li][li]C4D’s renderer is waaaay slower :wink: and there is in an insane amount of tweaking needed to get good GI/HDRI results.[/li][li]I had a hard time getting good HDRI results from Messiah. Check out this photo, it’s the original of the first one above. There are tons of white pixels everywhere. I tweaked settings for a solid 2 hours trying to get a decent reflection on my objects but never could get it to work.[/li][/ul]All in all though, it’s been informative and enjoyable. There’s no magic bullet or “make awesome and pretty render” button for either app, nor should there be, imo. I think I prefer Messiah’s renderer in the end because it is faster and slightly less cumbersome to work with than C4D’s although C4D tends to produce better results (mainly SSS).

Hope you found this informative or at least liked looking at the renders!

One interesting note: The look of the second object is coming entirely from the HDRI reflection…it’s just using the default material settings and a drab grey color. I thought that was pretty neat as it made a pretty convincing metallic texture.

#2

You might be able to get rid of the black artifacts by using area lights and also have a look at the transparency threshold in the render options which sets at what value a ray gets stopped (this optimises the render).

I know what you mean about the black bits in sss. I found that area lights often solve it but I havn’t tried the other method.

I would be interested in seeing how the C4D renders look in animation. The test I saw was flickery but maybe that was an older version?

#3

Thanks John, I’ll give area lights a try. I tweaked the various translucency settings, but did not do anything with lights.

#4

I believe the hotspots is due to Sharp, bright, high contrast pixels in the HDR image. This is from Worley’s Art of Noise:

HDR backgrounds
One of the worst grainy render situations is using HDR images for radiosity lighting. Sharp, bright, high contrast pixels in the HDR image can cause especially strong noise in both LightWave and FPrime renders. There’s a really easy and very effective solution which works for both FPrime and LightWave. The diffuse shading of radiosity doesn’t need any sharp details in the image, and in fact cause these sharp details are what cause noise. But mirror reflections of the backdrop do need a sharp map! So all we need to do is to make radiosity see a soft (blurred) map , but reflections see the sharp version of the same map. This is easy to do by simply blurring and reducing the resolution of the HDR backdrop image. Then use the original, sharp high-res map as a spherical reflection map (usually using Raytracing + Spherical mode in LightWave’s Environment surface editor tab). In the image below we rendered a ball with such a setup. The render times were the same, the only difference was in the HDR image map used.

I think it’s the way messiah handles the high contrast pixels - instead of being grainy like LW/Fprime, it develops white pixels everywhere. I remember this issue coming up with one of Weggs renderings of those eight spheres. It really depends on the HDRI map used.

As far as SSS goes, I have a list of things that cause artifacts. One of the main culprits is not having an object with Pregen Polys with not high enough SubD levels.

#5

C4D allows you to blur your HDRI…and the tutorial they have on their site uses an unblurred spehre for reflections and the blurred one for GI. Is there a way in Messiah to have a blurred image for GI to use and a precise image for a material’s reflection to use? I have not seen anything in the docs.

#6

Leebert: Is that the KitchenProbe HDR image that you’re using in the first image? If so I believe it’s the same one that was giving Wegg trouble.

I’m not aware of any feature in messiah that allows you to blur the image - I believe other apps that I have seen have relegated this to Photoshop.

Also, from what I’ve gathered in other apps, the HDR probe images tend to exhibit the sparkle effect that you’ve alluded to. It has something to do with a lot of data being crunched at the glancing angle of the chrome sphere.

Better results usually come from Hemispheric HDRI’s.

#7

Leebert, I just have to say that you have become THE MAN at abstract renders! I remember posting my zbrush tutorial a while back thinking “Damnit, Leebert is 100x better then I am!” :smiley: Those are some nice results on both ends of the renderers!

#8

Leebert, as far as I can tell the HDRI issue seems to be fixed in the beta . Until then just blur your image in Photoshop or similar application.
And one advantage of blurring by hand is that you can get by with a much smaller HDRI resolution. 512 or 256 pixel should be enough with a blurred HDRI. Speed up rendering even more. :smiley:

You are also contradicting yourself (or I am just not awake yet):

C4D seems to handle SSS better overall, although I think Messiah’s results end up looking nicer.

and later

…although C4D tends to produce better results (mainly SSS).

I really like the metallic look of the second one by the way. :thumbsup:

#9

I will experiment with blurring the HDRI and see what happens. I’ve also got a test SSS scene I was going to post for anyone interested in seeing if they could get it to look nice.

AlexK, what I meant was I like Messiah’s SSS because it is easier to set up and tweak when it works. Right now I just can’t get predictable results with it across projects though. So, overall C4D’s produces better results since I can get decent renders every time. But when I do luck out and hit the “magic combination” with Messiah it looks better, imo.

#10

I will experiment with blurring the HDRI and see what happens. I’ve also got a test SSS scene I was going to post for anyone interested in seeing if they could get it to look nice.

By all means share the test scene.

#11

I finally got a chance to do some tests with blurring HDRIs. It seems like a gaussian blur of about 15 pixels is the sweet spot…10 still produces quite a few white pixels and 20 creates too much of a blur…at least for the images I was testing with. I’m pretty happy with the end result, the only touchup I did in PhotoShop was to blur the back edge of the surface the object is sitting on. Everythign else is all messiah render.

Here’s the result (click for the larger version):

Also…here’s the sample SSS scene for anyone interested to take a look at…as you can see…lots of harsh shadows (click for project file):

#12

It´s a bug it must be, it´s like the rays die after to many penetrations in and out of the object.

EDIT. Ha I know what it is, the rays die after they enter and exit a solid object 3 times.

#13

Which you are able to adjust with the Ray Depth (I think it is called) parameter. It is sitting right below the Motion Blur settings. I think you have two, one for reflections and one for refractions. :thumbsup:

#14

Already tried that one with no luck. But thats the place they should put the new Translucency Ray Depth setting :smiley:

#15

That is what TLHPro:RayType is made for. You can have different materials for Camera Rays, Reflections, Refraction (Transparency), GI and Shadows. :slight_smile:

For GI Lighting, it is also a good idea to simply scale the HDRI way down to something like 100-200 pixels f.i. in Photoshop (CS2 finally does HDRI). Some HDRI collections already come with such images. The 3D app then interpolates the pixels and “blurs” it for you with little memory and computation overhead. While you loose a bit of detail in the light, you can get rid of a lot of artifacts.

You can also use a simple gradient for GI and a HDRI or Photo for Reflection/Refraction.
I actually use RayType in almost every rendering I do.
It is also a nice way to have the same material on Environment and Background and control everything with RayType in one material. Only the needed shaders are evaluated so it is fast too :wink:

Cheers, :bowdown:

#16

AAAron, I will submit this example to pmG support and see what they say.

Thomas, looks like I need to grab me a copy of TLHPro! :wink:

#17

I would give them a setup that looks like this instead:

You will see how the light only penetrate the three first columns but travel through the bottom according to the light penetration setting.

And TLHpro is great, a must buy, the easyglass shader and raytype are essential for using messiahs renderer to the full.

PS. I don´t have my license avaible right now so I´cant do the setup my self. BTW. your HDRI stuff looks great, you got me playing with Topmod too, really cool app. :slight_smile:

#18

Leebert,

Though I whole heartedly endorse the purchase of TLHPro. I may be missing something with the example you posted. Because If you changed the light type to sphere and adjust the intensity and diameter will you not get the desired results?

R

#19

Some mix up here, the THLpro is for the HDRI stuff aka. different hdris for reflection and lighting. The translucency stuff is a bug. The reason it looks better with a sphere light is because the rays are coming from all around the sphere so avoids some of the holes in Leeberts topmodel :wink:

#20

Hmmm … I’ll have to check that out. In my SSS thread … I did a study of an object within and object (bone shader) having essentially 8 layers … curious.