Sunday, November 7, 2010

Vray For Maya: Vray Material Part 2

Here's the 2nd part on the vray material. It covers the refractive portions of the material, some extra bits, and the very simple, blend material.

Thursday, November 4, 2010

Posted the next video in the Vray for Maya training series. This one is on the basics of the Vray Material. It had to be broken into 2 parts, so the next one touches on the Blend material, and finishes the Vray Material. Sorry to have it messy like that, but I record, and don't track my time very well;)

Tuesday, October 26, 2010

Vray for Maya: Vray Frame Buffer

This video goes over how to use the Vray Framebuffer, and its integration into Maya. Hopefully it helps your (linear) workflow.

Vray For Maya: Nederhorst Settings

This video gets you up-and-running with some production-proven render settings originally outlined by Robert Nederhorst. Thanks to him, and the Chaos Group team, we have some really useful and simple ways to render complex scenes. It may look a bit tricky at first to set it up, but by all means, save it a preset. I use a preset and apply it at the start of my scene, then set the vray common attribs afterward. You can also text edit the preset, and comment out all the bits that modify the common tab.

Thursday, October 14, 2010

Vray Training Videos

I thought I'd take a bit of time, and record some videos to introduce folks to Vray for Maya. This is mostly geared toward people already familiar with rendering with raytracers (like Mental Ray). It won't go over very basic concepts, but it will introduce vray in such a way, as to get you producing nice images with it quickly. It was initially thought of as internal training videos for my company. We get a lot of freelancers in that have experience with MR, but not with Vray. So I often spend time with them going over the same stuff over and over. So this will help everyone!

So far, only the first few are up on my youtube channel. The introduction in 2 parts, and an overview of "Nederhorst Settings" which are solid, easy-to-use and production-proven settings. I plan to add more soon. Next ones should be, the Vray Framebuffer, Materials, and Lights.

Intro Part 1

Intro Part 2

Tuesday, August 31, 2010

Arnold, My Old Friend

Marcos, the creator of the Arnold renderer in use at Sony Pictures Imageworks was recently interviewed. Fun read. In an email conversation with him, he pointed out some recent papers he was directly and indirectly involved with. They too are worth reading if you are into raytracing.

Physically-Based Shading and Lighting at SPI
Siggraph 2010: Course on Global Illumination

And for added fun, here are some wayback renders done in the early versions of Arnold for 3dsmax. Some of which I did;)

Vray vs. Mental Ray

I have gotten some requests to expand on my transition to Vray so I'll take an opportunity to do so.

What sold me on Vray during early tests was its general speed at handling GI renders. Without getting into specific benchmarks, it was pretty clear to me that Vray had a substantial speed gain in complex GI scenes. The other major influence was "The Nederhorst" settings, as they have come to be known around here. These settings leverage Vray's powerful Deterministic Monte Carlo (DMC) sampler. The general idea is to minimize the amount of settings you need to tweak to affect your render quality. In production, as in life, simpler is better.

The specifics are here, but the general method is to tell Vray's sampler to be fully adaptive, so it will refine samples only in areas that need it, based on a simple contrast threshold setting. This sped up our productions significantly, as we needed to do much less tweaking to get quality renders.

This is what prompted the switch. Since then, Vray has grown in features, and I can confidently say, that it is now better integrated into Maya than MentalRay. It has added hair rendering, will render its own fur, fluids, particles, and has a much easier-to-use pass system. We consistently spit out custom channels for material id, AO, Z, normals, and other custom textures, in one neat-and-tidy render. Vray negates ever having to touch Maya's renderpass system, and makes our lives much nicer.

Another benefit is in Vray's handling of "Linear Workflow." With a click of a button, Vray will adjust all input colors/textures to any gamma you like... thus compensating for the 2.2 baked-in gamma of most textures and colors in Maya. We really don't even think about linear workflow, as we are always in it. Using the Vray Framebuffer, you can dynamically switch on sRGB compensation, to adjust your linear image to monitor-space for quick evaluations. You can plug in your own LUT, you can quickly add your own curves in the framebuffer to imitate what color treatments you may apply later. It adds linear workflow to Maya in the way it should always have been done.

Another great addition is the easy-to-use distributed rendering. We do a lot of hires print images. 5-15k. So no GI renderer on a single machine will be speedy. With a dedicated set of machines on a farm, you can toggle a button and harness many machines to attack a single frame. 5 k renders done in minutes, as buckets race across the screen. While MR standalone will allow you to do this as well, you'd have to invest the extra bucks for that, and Vray is still faster and easier to set up.

Lastly, VrayRT has appeared in beta form, and is now changing the way we light once again. We have already put it in production on our latest automotive renders, with great results. VrayRT-GPU may again change things in just a few more weeks. We look forward to using the additional horsepower already in our towers.

So, that's the sales pitch;) Really, it has been a great ride in the last year, and I thank Chaos Group for working so hard on this product.

Monday, May 10, 2010

First Vray tests (from 1 year ago)

So, I haven't been updating very much in the past year (sorry), but here's some new info. As mentioned, I've switched to vray. This was the first thing I made while testing it (around April 2009).

Some things to note about this image:

It is an "impossible" lighting setup in the real-world, and when we are tied up in physically accurate lighting, we need to remember that lighting direction doesn't always have to follow real-world rules. The goal of this image was to recreate a particular composite of images where lighting was tuned for each specific part of the interior then combined in photoshop. The overall image works, even though lighting cues/directions are all mixed up.

There are about 30-40 rectAreaLights in the scene, split up into "zones" and there are lots of light exclusion/linking going on to keep one zone from affecting another zone. Zones were broken up into seatLeft, seatRight, Steering Wheel, Side Door, Shifter, Dashboard, and Dashboard Central. This render is just about raw from Vray, and very little has been done to it other than some retouching and minor CC.

I wouldn't call it totally finished, as there are some texture problems, and could use some post love and color grading, but this served as a great test to see how our switch to vray might go. I took about one week to produce this image, from having never used vray before. I'd say this image has some very inefficient render settings, since I wasn't quite versed, but the quality and relatively low learning curve (from MR) convinced us to make the switch.

Friday, February 12, 2010

SLIK Studio Lighting Tools

Here's a link: SLIK

Now, while this seems cool, it feels a bit overkill. Here's what I like:

- ies profiles for each light. That is cool, and useful.
- high detail for the illuminant surface
- a model library of lights for when you need them.

Now I'll discuss what I think is wrong. The obvious being... that's a lot of heavy geometry for a scene where I'd prefer my heavy geo be in my product. This seems like a way to slow down fluid production. Friendly controls are ok, but really, how hard is it to adjust the intensity of a light in the lights attributes? Do I really need on-screen controls for this cluttering up my workspace?

Yes, I get that the end product could be a simple hdri... but why? Why substitute the control of individual lights for an hdri when you don't have to?

Here's a suggestion for an alternative. I wish someone would produce this so I could buy it, since I don't have time to make it all myself (hint hint, wink wink). Simply photograph lighting equipment in HDR. Then you have an accurate image (with all the detail and folds, and tape marks, and whatever floatsYerBoat). Place those images onto your area lights in MR/Vray and have fun. Light (geometrically speaking), easily adjustable, no need for models beyond cards and lights. For direct lights, ies files would be great.

SLIK seems fun, but it wouldn't really help production fluidity for me, and I do a lot of product imaging. It would be cool if you need to render the guts of a photo studio tho;)