Keep up-to-date with Free tutorials!!

 

Sign up to our twice-monthly newsletter today for the latest tutorials, interviews and product information.

Sign me up to receive third-party emails from 3dtotal's partners, too!

- Latest news
- Exclusive Shop Offers
- Preview early content
- Plus much more

 

Not Ready to take that step? OK, Why not just Subscribe to the RSS Feed

 
submit tutorial
1 | 2 | 3 | 4 | 5
Indirect Illumination with Mental Ray

By Andrew Klein
| Your Rating:
rating star nonerating star nonerating star nonerating star nonerating star none
(0 Votes)
| 89136 Views
| 0 Comments
| Comments 0
Date Added: 9th December 2009
Software used:
Maya, mental ray

In the following two images, both of the GI and FG Rebuild features have been turned off, forcing Mental Ray to re-use existing maps. Notice that when I move objects or the camera, things don't quite look right. However, in both renders, the render time was an amazingly fast 8 Seconds! This is because I am not rebuilding anything at all, and thus the render takes just as long as if FG and GI were turned off (Fig.30 - 31).

482_tid_Fig_30.jpg
Fig. 30

482_tid_Fig_31.jpg
Fig. 31

Rendering Caustic Effects: Caustics are light patterns that are created when light from a light source illuminates a diffuse surface via one or more specular reflections or transmissions. Examples are the light patterns found on the bottom of a swimming pool as light is refracted by the water surface; light being focused by the refractive value of glass onto a diffuse table; light emanating from the headlights of a car as light is refracted from the bulb off the back parabolic mirror; light being refracted inward by gold, a precious metal. Notice the common theme here. Refraction is the key to seeing caustic effects. In the following image, the red dots show several occurrences of caustic light (Fig.32).

482_tid_Fig_32.jpg
Fig. 32

To Enable Caustics, let's go into the Render Settings window and turn on Caustics (Fig.33).

482_tid_Fig_33.jpg
Fig. 33

We are also going to need to tweak our settings. Usually, I will make my Caustics Radius the same value as my GI radius (Fig.34).

482_tid_Fig_34.jpg
Fig. 34

Next we are going to need to make a refractive/transparent material to let light through. It's not enough to just set up refractivity. If you are using a Maya Material (Blinn, Anisotropic, Phong, etc.), you will need to add a photon shader to your material so that it can focus the photons into a caustic highlight. If you are using a Mental Ray material (DGS, Dialectric, MIA), these already have built in photon shaders so you won't have to do any extra work. Here is a look at the differences between the Shading Groups for a Maya Blinn, and a Mental Ray MIA material (Fig.35).

482_tid_Fig_35.jpg
Fig. 35

If you are using a Maya material, you can input the photon shader like this (Fig.36). And Render!

482_tid_Fig_36.jpg
Fig. 36


Notice how we now have a beautiful green tinted highlight in the middle of the shadow for the green crystal ball (Fig.37).

482_tid_Fig_37.jpg
Fig. 37

That's it for Caustics, and for this tutorial. I hope you were able to find it useful. Now get out there and render something pretty!




< previous page
 
1 | 2 | 3 | 4 | 5
Related Tutorials

Tutorial

Gallery Image.



Keywords: global, illumination, indirect, teapot, max,

Go to tutorial
rating star nonerating star nonerating star nonerating star nonerating star none (0)
Comments 0 Views 40600

Tutorial

Gallery Image.



Keywords: Making of, Project, Arch-viz, Building, Architecture, Lighting, 3ds Max

Go to galleries 1
rating star fullrating star fullrating star fullrating star fullrating star full
Comments 2 Views 30411

Tutorial

Gallery Image.



Keywords: Making of, ZBrush, Maya, Photoshop, Fantasy, Alice, V-Ray, Mudbox, NUKE

Go to galleries 1
rating star fullrating star fullrating star fullrating star fullrating star half
Comments 1 Views 27848

Tutorial

Gallery Image.



Keywords: House, Arch-viz, Scene, 3ds Max, V-Ray, Making of

Go to galleries 1
rating star fullrating star fullrating star fullrating star fullrating star half
Comments 3 Views 36599
Readers Comments (Newest on Top)
avatar
(ID: 238516, pid: 0) Elise on Tue, 10 December 2013 10:26pm
The way you explain GI and FG is the clearest i've ever found. All of your definitions are humanly understandable - as opposed to Maya's aweful manuel. Thank you for creating this!
avatar
(ID: 151509, pid: 0) DoctorBeat on Sat, 22 September 2012 12:33pm
You saves my life man! Thank you http://forums.3dtotal.com/showthread.php?p=927194#post927194
avatar
(ID: 136011, pid: 0) Jun on Thu, 26 July 2012 3:37am
Hi, This tips are very useful for me. It helps me understanding mental ray. Thanks very much!
Add Your Comment