maya he3d

Since I don't get the time to update this blog much anymore, I thought I'd just drop in quickly to recommend a google groups mailing list that I have been contributing to for a while now. If you feel like some question/answer type discussions focused specifically on problem solving in maya this might be the place for you. There are a great bunch of knowledgeable people posting there already from time to time, but more will always be welcome. Just enter "maya he3d" in the google groups search.

maya paintFX leaf UV layout script

david | mentalray,python,rendering,vray | Thursday, March 10th, 2011

Update 2012-07-28: The script has been updated with new features, which include a user interface replacing the command-line stuff. The leaf layout details explained here are still relevant and correct, except for the command to run the script. The new command can be found at the end of the new post.

There is a long, long thread on cgTalk called "Forests in maya mental ray".  The discussion is all about techniques for creating and rendering the vast numbers of polygons needed to make convincing grass and trees in large numbers.

Maya's paintFX can be used to make trees which can be converted to polygons with leaves that consist of just a few polys per leaf. Texture maps (color, opacity, bump etc) are then applied. The default output from the paintFX conversion has each leaf mapped to fill the standard uv quadrant, so each leaf gets a copy of the texture. This can look pretty good, but the repetition is usually very obvious. You could break the leaf mesh into a few parts and assign variations of the leaf textures to each part. But a more efficient way is to layout the uv's so that groups of leaves are mapped to different parts of the uv quadrant in a 4x4 tiled patternfor example. Then you can make a texture map with leaf variations arranged in the same 4x4 tile pattern. Now you can have 16 different looking leaves on the tree, almost as easily as you can have one.

Default paintFX conversion gives you this


But what you really want is something like this 4x4 tile pattern (or maybe 2x2 or 3x3)


The problem is that you might have 50,000 leaves on your tree. It would be very difficult to select and edit the uv's for different leaves by hand. This is something that needs to be automated (more...)

workaround for AEhardwareTextureTemplate.mel bug

david | dj mod,mel script,mentalray,rendering,vray | Wednesday, January 26th, 2011

Ever since I can remember, maya has had an annoying bug that causes materials to display incorrectly in the viewport in both "Smooth shade all"  and "Textured" modes.

If you've ever encountered something similar to this error

// Error: file: D:/Program Files/Autodesk/Maya2011/scripts/AETemplates/AEhardwareTextureTemplate.mel line 721: Found no attribute match for "mia_material_x1.diffuse" //

or this one

// Error: file: D:/Program Files/Autodesk/Maya2011/scripts/AETemplates/AEhardwareTextureTemplate.mel line 827: Object 'VRayMtl_qualityMenu' not found. //

then you may be interested in a workaround. Its not perfect, but its better than nothing.


then one day you find ten years have got behind you

david | mel script,mentalray,nuke,opinions,python,rendering,vray | Wednesday, January 5th, 2011

Miss Hollywood

This time last year I started a new job at a new studio. For me, this was a big change since I had been at the previous studio (one that I helped build from almost nothing) more than 20 years.

My new job has given me the opportunity to learn several new applications and as a result I have found little time to update my blog and it has been very much neglected.

So to begin a new year of enthusiastic blogging, I've decided to write a (long, possibly boring) post about what I've been doing the last 12 months. It is just a quick rundown of changes affecting my general workflow. If you are still interested, keep reading (btw... the photo is my new puppy, Hollywood) (more...)


david | dj mod,mel script,mentalray,rendering,tutorials | Monday, August 30th, 2010

You can use this script to create black and white matte renders using mentalray's pass system which means that it takes no longer to render 100 mattes than it does to render one. And since the script makes it so easy to set up these passes you can render a separate matte for every object in your scene, if thats what you want, or for combinations of objects that you select or based on the materials that are assigned. (more...)

More stuff about Linear Workflow

david | mentalray,rendering | Sunday, July 18th, 2010

Earlier this year I wrote my two step guide to Linear Workflow. Since then I have received a lot of email about it. It's a tricky one to explain in simple terms. I did my best to narrow down my description to cover the basic concepts. Some people got it. But I can tell from the email, that others saw gap's that I did not adequately fill.

Luckily for all of us. Fredrik Averpil has written an excellent article on Linear Workflow in Maya 2010 with pictures and diagrams and examples of how this also applies to compositing in Nuke 6. You can check it out here.

createMentalRayIndirectLightingTab.mel updated for maya 2011

david | dj mod,mentalray | Thursday, July 8th, 2010

The title says it all. The original post is here if you don't know about this one.

how to add bump map to car paint phen

david | mentalray,rendering,tutorials | Friday, March 12th, 2010

Here's a simple method you can use to add a bump map to the mi_car_paint_phen_x material without using custom shaders or complicated shading networks.


Maya Linear Workflow In Two Steps

david | mentalray,rendering,tutorials | Sunday, March 7th, 2010

If the emails I get are any indication, then I'd say there is a fair amount of confusion around the subject of linear workflow in mentalray for maya. And over the past few years in my search for answers I have contributed my share of half truths and misinformation to the discussion. So, in the next few paragraphs I'm going to state simply and without detailed explanation how to achieve a linear workflow in mentalray for maya by doing two things. Simple! (more...)

frame by frame command line rendering

david | mentalray,rendering,tutorials | Wednesday, February 17th, 2010

If you don't have access to a render manager, or even if you do, you might want to render from the command line one frame at a time. There are a few reasons why you may want to do this. Sometimes maya does not get to the end of a long batch render due to memory errors. You set off a 100 batch and it dies after frame 27 maybe. Another reason is that sometimes your animation does not seem to work in a batch render. A single frame renders correctly, but when you batch it some things don't update correctly. (more...)

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