Rendering Tutorials Archive

21 “must see” Mental Ray tutorials

Although I am not a mental ray user, I realize that it is a very powerful rendering engine and it is being used by a lot of readers. Therefore, I have compiled a list of 21 mental ray tutorials that I think worth a look. Some of them are new, some of them are old, but still there is a lot too learn from them.

1)  How to use mental ray ambient occlusion as a separate pass.

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15 Essential Vray Tutorials

Here is a list of 15 vray tutorials that I think everybody should read. It covers everything from materials and shaders to illumination and rendering settings.

(And yes, I have included 3 of mine tutorials in the list :) )

1) Critical vray  settings
Without any doubt, this should be the first one on the list. It’s an in-depth analysis of all the critical vray settings that affect your scene one way or the other. It covers topics like irradiance map settings, image sampler, lightcache settings and more.

2) How to create incredibly realistic grass
Although you will need a really powerful workstation in order to use the technique shown in this tutorial (especially if you have large areas of grass in your scene), the results are truly amazing.

3) How to create a lampshade material
A tutorial that explains how to use the vray2sided material in order to obtain materials like lampshades, curtains, etc.

4) How to setup a sky scrapper rendering
This is a very interesting tutorial that shows you a very unconventional way to setup a rendering of a skyscraper at night.

5) Night exterior illumination
A tutorial that explains, in a systematic way, how to setup the illumination for a night time rendering of a small villa.

6) Daytime exterior lighting
A tutorial that reveals a method to light an exterior scene in vray, using image based lighting.

7) How to render an architectural scene with hdri
A classic way to light an architectural rendering using hdri

8) Night interior rendering tutorial
An interior rendering tutorial that explains  how to setup a night illumination rig with vray

9) How to render realistic snow with vray displacement

10)  How to setup and render convincing materials like chrome, silver, stone and glass

11) How to use hdr images (hdri) in vray
A tutorial that takes you through all the necessary steps to use hdr images in your scenes

12) How to render a liquid in a glass
Rendering a liquid in a glass can prove to be problematic. If you model it like in real life, the polygons located at the interior of the glass will be microscopically close to the geometry of the liquid, which can result in coplanar faces and therefore, artifacts when rendering.
Checkout this tutorial to see how you can avoid all that trouble.

13) Gamma 2.2 or Linear Workflow (LWF)
A very well documented tutorial that talks about every aspect of working with gamma set at 2.2
When this concept was introduced for the first time, it generated a lot of buzz. Most people couldn’t get it to work right and their resulting renderings had either the colors or textures washed out. This type of workflow is a bit different than the traditional way, so if you miss a step you get unexpected results.
Fortunately, this tutorial explains each and every step very clearly and it also sheds some light on the theory behind the concept of linear workflow.

14) Vray studio lighting tutorial
A comprehensive tutorial that explains how to create a studio lighting in rig in vray.
This is especially helpful for art directors or furniture designers.

15) How to create various reflective shaders and caustics

If you know more vray tutorials that you think I should add to the list, feel free to post a comment with links to them.

How incorrect geometry can affect the lighting of a 3d scene

A little introduction
After having written the latest tutorial on linear workflow, I have received an email from Jackie (a frequent reader of this blog), who claimed that he had followed the instructions shown in that tutorial, but still ended up with washed out renderings.
After having seen the rendering that he had attached to that email, I suspected that he had missed one or more steps.
So I asked him to send over the scene, and promised to do a case study which initially I thought it would be something like “be sure not forget to…. when using lwf”.
It turned out I was wrong; Jackie had followed every step of the tutorial, but still ended up with a rendering that was lacking contrast a bit.
What was the problem then?

Take a look at the following 2 renderings: (click to view a higher res version)

Would you believe that those are rendered with the same lighting and rendering settings?
Actually they are. The only thing that is not the same is the geometry.
I realize it may sound strange, but the way you model your scene may have a very big impact on the lighting.
Take a look at the following renderings:

As you can see, the way the geometry is modeled, environment lighting is getting into the scene through all the wrong places. There is no wall behind the camera, the ceiling is only modeled where it is visible in the camera viewport, etc, etc.
Also, because of this, the lighting cast by the “light emitters” bounces out of the scene in an unnatural way, and all this will only result in a rendering that lacks contrast.

Bellow are a few images that illustrate a few changes made to that scene.

As you can see, the walls are modeled even where they are not visible in the view. The only thing that I left out (on purpose) is the area above the staircase (where there is actually a vray light that simulates a diffuse lighting source that is not directly visible)

Although this may not seem like a regular “3d lighting tutorial”, looking at the differences between the 2 scenarios, made me believe that this can be even more valuable than a “step by step approach to interior lighting with vray”.

Most of the times details like this are overlooked in regular tutorials. I am absolutely positive that I wouldn’t have thought to write about something like this if Jackie hadn’t mailed me the scene.

The conclusion that we can all draw from this is that no matter what rendering engine you use, be it Maxwell, vray, brazil, fryrender, mental ray, it can not calculate correctly the lighting of your scene if the geometry is somewhat incomplete or incorrect (doesn’t matter if the rendering engine is physically accurate or if it uses a biased solution).

Note: In order to make this tutorial more clear and simple, I have modified a little the scene that Jackie had initially sent me. His scene was a little bit more complete, but still the effect was visible so I had to make it even more visible, just for the purpose of this tutorial.