Maya FX
Dust and Spark when Skates hit the ground:
If you want the skates to kick up some dust while he's skating frantically, you may want to write a conditional expression that emits dust while the skate's translation is at y=0 all before the stop (where X or Z might be less than a certain number) or while the time is less than his final trans keyframe. Better yet, calculate the dust emision based on his velocity to emit more when he's going faster.
Answer from Maya-Listserv on Highend3d.com (D.W.Kim, 10 Jan 2001 15:49:19)
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Other Way:
You could create an expression on the rate of the emitters based on the Y value of your skates. (in a Y -up world) for example
If skates.translationY = 0 then emitter rate = 10
else emitter rate = 0
Or with a set driven key...
key emitter rate 10 when skate translation in y = 0
and key emitter rate 0 when skate translation y > 0
Answer from Maya-Listserv on Highend3d.com (Peter Pankras, 10 Jan 2001 19:35:46)
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Realistic Fire
- Create a cylinder in the rough shape of a flame. (Bulbous at the bottom, tapering off at the top)
- Create a tight spiral around the shape by:
a. Create a degree 1 EP curve-on-surface.
b. Move one point using "move -r -100 1" - mess around to get the right numbers
- Attach a PaintFX stroke to the curve on surface
- Edit the brush: (make stroke display quality 100%)
Tubes = ON.
startTubes = 1
tubesPerStep = 0
brushWidth = 0
softness = 0.9
stampDensity = 2.5
pathFollow = 1
lengthFlex = 1
tubeCompletion = off
On the stroke make the sampleDensity a high number, say 6000
Now increase the tubeSegments until the tube just makes it to the top of the cylinder (the tube should exactly follow the curve) tube width just wide enough to make the lines in the spiral merge into a surface play with incandescence to get a good glow transparency near 1.0 play with a little tip fade
- Animate the soft fuzzy tube.
On the brush:
displacementDelay 0.3 or so
turbulenceType = worldDisplacement
interpolation = smooth over time and space
turbulence = 0.1
turbulenceFrequency = 2.5
turbulenceSpeed = 0.5
- Hide the underlying cylinder and render
Answer from Maya-Listserv on Highend3d.com (Duncan Brinsmead, Wed, 07 Feb 2001 13:16:06)
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Using cloth dynamics with PaintFX hair:
- Create some guide hairs... (see the PaintFX hair tut on Highend3D.com)
- Use these curves to extrude to tubes and convert them to Polys
- Make them cloth objects and constrain (cloth) the start of the tubes to your head.
- Make your head a collision object
- Select edges on the polytubes and convert them to curves with construction history (this way the curves will follow the movement of tubes)
- Paint around each poly tube PaintFX hairs (see PaintFX hair tut on Highend3D.com) and following the rest of the tut (with settings for the PaintFX stroke)..
Answer from Maya-Listserv on Highend3d.com (Peter Pankras, Tue, 9 Jan 2001 13:56:41)
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Has anyone tried to do nice time lapse storm clouds in pfx?
Your best bet would be to replace the file texture used in the brush "cumulus" with a real photo sequence( preferably one with good quality alpha ). To use the animated sequence toggle on "UseFrameExtension" and keyframe the extension value. Depending on the nature of the alpha you may need to turn off fringeRemoval( if you see glowy fringes ).
If you don't have an animated sequence, you could try playing with animating the smear and offset values on the texture. Once you have a brush you like paint the sky with small short strokes( this avoids some problems with an animated viewpoint ).
Answer from Maya-Listserv on Highend3d.com (Duncan Brinsmead, Wed, 28 Nov 2001 12:20:01)
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PaintFX performance issues
When one paints strokes nurbs curves are generated with very dense cvs. Displaying these curves can consume a fair bit of refresh speed, so by default they are hidden. One the paint effects menu there is a utility to reduce the number of cvs in your curves without changing the look of the paint effects strokes:
Curve Utilities-> Simplify Stroke Path Curves.
Reducing the number of curve cvs can dramatically speed things up in some cases, especially if you painted a surface that is deforming. The paint effects curve simplify drops out odd points, rather than looking at curvature, in order to preserve the distribution of tubes along the stroke. You can run it multiply times on the same set of curves to further simplify them, although small features in the shape of the path curve will be lost.
I suggest reading the sections on optimizing in the paint effects FAQ on highend3d.com.
Answer from Maya-Listserv on Highend3d.com (Duncan Brinsmead, Wed, 28 Nov 2001 12:09:29)
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Image for Painteffects brush
On the performance side.. the number of segments can get high if you make the stem short an there are twigs. Making the stem a little longer and lowering the number of segments to the minimum can help.Also lower the stamp density as much as possible. Lowering the quality setting on the stroke for the interactive redraw can make playback much better.
For the image map approach render one of your puffballs as a square maya iff with alpha against a black background(or paint one in canvas mode and save). The alpha will work well if you do this and then use the fringe removal feature on the brush texture.
Use the brush pineTextured as a starting point, changing the tree image for yours and making texColor1 white and setting the saturation on transparency2 to zero. Set the Specular color to black. You may also wish the translucence to be 1.0. Also look at the Hue Sat and Val rand settings. To fit the image better, you can adjust the tube width vs. height. Also you can lower the number of segments if you don't want them to bend.
Answer from Maya-Listserv on Highend3d.com (Duncan Brinsmead, Tue, 27 Nov 2001 19:44:35)
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Compensate flow animation
The mel command freezeBrushTexture automatically sets up an expression on the u offset to compensate for the flow animation. Select your strokes or brushes and simply type "freezeBrushTexture".
Answer from Maya-Listserv on Highend3d.com (Duncan Brinsmead, Tue, 20 Nov 2001 10:41:41)
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Paint Effects Shadow Madness
You should turn off Use Dmap Auto Focus and midDist maps one the lights shadowing the paint effects, if you haven't already. Particularity with AutoFocus if you turn off all other shadow casting objects this could affect the shadow boundaries, because paint effects strokes are not checked for the auto focus.
(and make sure receive shadows is on for the surface)
Answer from Maya-Listserv on Highend3d.com (Duncan Brinsmead, Fri, 16 Nov 2001 14:17:27)
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Glow flickering
Leave Auto Exposure on (Glow and Halo intensities at default 1), and do some render tests to find a frame in which the glow looks good to you. Open the Output Window and note the two "intensity normalization factor" values near the bottom. Plug the first value into Glow Intensity and the second into Halo Intensity, then turn Auto Exposure off. If you want to render your testframes at a lower-than-final rez, do this through the Render View Options>Test Resolution, and not by changing the Render Globals rez. If you happen to need to up the rez in Render Globals at some point after attaining a glow "look" you like, use the formula: glow intensity / (rez scale
factor)^2.
or
render one image with auto on, write down the exposure blabla numbers, which you seen in the output window, turn auto off and type in the numbers by hand. best you render a part of the image in 1:1 res and check if the glow ist alright.
the auto exposure changes the glow values depending on some factors I don't know ;-), but the result is the flickering...
Answer from Maya-Listserv on Highend3d.com (Eric Brock & Lars Gerstenmaier)
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Light and Painteffects
First off make sure you have realLights on for the brush. The highlights will change with the lights, but at the same time are modulated with the texture on the surface(this helps with stuff like bark and hair ). We could have added another button to enable-disable this behavior, but there are already a lot of buttons.
Also the specular is only computed per vertex of the tube, not for each pixel of a stamp. A tube specular model is used(similar to anisotropic hair models). You cannot get the small focussed highlights like you might get on a shiny phong surface, although sometimes increasing the number of segments can help.
At some point I would like to add the ability to do a more standard specular highlighting.
Answer from Maya-Listserv on Highend3d.com (Duncan Brinsmead, Fri, 16 Nov 2001 14:17:27)
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Fix brushes
Not at all. Select all the brushes:
select `ls -type brush`
Now open the spreadsheet editor and adjust the desired parameters(if you have a lot of brushes this is easier than using the attribute editor ). Or if you painted all the grass using the same brush, select all the strokes and then invoke
paintEffects->shareOneBrush
Now there is only one brush that needs to be changed so you can easily do the edits in the attribute editor.
Answer from Maya-Listserv on Highend3d.com (Duncan Brinsmead, Wed, 27 Jun 2001 09:16:37)
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