particleSamplerInfo update

david | mentalray | Monday, July 21st, 2008

I added some more screen shots to yesterday's post as well as an example scene file download. If you had problems with the mp4 movie there is now also a link to a sorenson3 version. If you are on vista 64 then the embeded movie wont have any controls (due to a quicktime limitation) but if you scrub along the bottom you should be able to get it playing.

particleSamplerInfo smoke

david | mentalray | Monday, July 21st, 2008

In the past few years I have often been asked to create smoke for a variety of different visual effects. There are many ways to do it in maya using particles or fluids so I choose one that suits the job. Last week I needed to use particles and that led me to an interesting discovery - how to use the particleSamplerInfo node.

I had seen it before, in the hypershade Create menu, but I'd never tried to use it. But then I stumbled upon this archived post on cgtalk where Anders Egleus said

I've recently tested rendering particle clouds in mentalray instead of maya software and I'm very happy with how mentalray shades and motion blurs particle clouds.
...
It seems that turning on the local attribute in the 3d texture doesn't seem to have any effect when rendering with mental ray. No matter how I try, the particles seem to "swim" through the texture.

For years I've been rendering particle clouds (with the software renderer) and I didn't realise that I could turn on the local attribute in the effects tab of the texture node to stop the particles swimming through the texture. I've always done things like animating the place3dTexture node or the texture's time attribute to try and hide it, but was never totally satisfied with the results.

These days I use mentalray for most things and I also like the way it shaders particle clouds, so I wanted to fully understand the rest of Anders' post. Read on to see where it got me. (I'm very happy with the result). (more...)

djParentShape.mel

david | animation,mel script | Sunday, July 6th, 2008

I've been doing a fair amount of rigging where I use joints and empty groups as controllers. I try to minimize the need for going to the outliner to select things by adding shapeNodes to these controllers so that they can be selected directly in the viewport.

To parent a shapeNode to a different transform you need to use the command

parent -r -shape;

but often you'll get the shape jumping to a new location when it adjusts to its new parent. If that happens you can select the cv's or verts and move them to where you want them, but if you are doing this alot it can get messy and becomes time consuming. And that was the motivation for writing djParentShape.mel

With djParentShape you select the new controller object, shift-select the joint and run the script. It has two modes of operation: move to position or preserve position so you simply choose the one you need.

Download from here.

Keep reading for details... (more...)

toggle hypershade thumbnail updates

david | dj mod,mel script | Friday, July 4th, 2008

A few weeks ago I saw this thread on cgtalk where Matt Estela offered a workaround for the slowness that we experience when using the hypershade when complex shaders or shaders with large file textures are involved. The update lag seems worse if some of the new mia shaders are involved. Matt's workaround is to simply disable the thumbnail updates while you are changing attribute values and to re-enable the updates again later when its more convenient.

I spent some time modifying a maya2008 sp1 mel script called hyperShadePanel.mel to add Matt's suggested workaround to a new button. Its the one with the little green shader ball icon in the center collumn as shown here

thumbnailUpdatesToggleButton.jpg

You can use it to toggle thumbnail updates on and off. You'll get one of those purple warnings in the info window to tell you the update state has changed.

warningMessage.jpg

You can download my modified version with the button icons from my downloads page. Put hyperShadePanel.mel in your local scripts folder and the xpm files in your icons folder and you'll get the new button when you restart maya.

Download here.

I previously uploaded an earlier mod version soon after reading the cgtalk post, but the button behavior was slightly awkward. This has been corrected now, so this note is for anybody who tried it before - its better now.

20 May 2011 update: I've added a version that works in maya 2012. The rar file now includes the new mel and 2 new png bitmaps for 2012.

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