Hi, I am following the tutorial software.primefocusworld.com/sof … dering.php
is everything clear but when I used the Temperature Channel i have problem to obtain the same result.MagmaFlow is the same of tutorial the problem begins in the second half, when A Gradient Ramp texture map was added to Override the Emission of Krakatoa slot and set to use Mapping Channel 1 (TextureCoord).
first question: why applying the gradient map to override the Emission of Krakatoa instead to apply it as diffuse map of a material and apply this material to the grid of fumeFx? the tree of magmaflow should not transform the temperature of the grid of fumeFx in UVW space of particle?
second question: why ,if I follow the tutorial and add a gradient to the Emission Override not get the same result?(I get just the left color of the gradient)and, How do set to use Mapping Channel 1 in the Emission Override ?
third question: and why if use emissions is active and the gradient is applied as material of fumeFX Grid, the shadows disappear and when I applied a different gray material to fumeFX Grid this material is mixed with part of the gradient and the shadows appear? see attached
Thanks and sorry for my English
I hope I explained
I applied the Gradient to the Emission because I was trying to render FALSE COLORS and did not want any lighting/shading on the particles, just flat color. You cannot get that without making the particles emit the light themselves (self-illumination = emission), so I opted not to use the Diffuse channel. But you CAN, and you will need a light to illuminate them.
Applying a Material to the FumeFX would not work because we need to generate the UV coordinates BEFORE the Gradient Ramp is evaluated. Since all Overrides found in Global Render Values are applied AFTER the particles have been loaded from the scene into memory, the Gradient, if applied directly to the FumeFX, would find no UVs and will look Blue (because that’s the color at U=0).
I don’t think your setup is wrong, but it is quite possible that the Temperature channel has different values than the one I used. Have you tried changing the 0.03 multiplier to a higher value? Does the color change then? For debugging, you could switch to Save Particles mode and write to a CSV file (which is an ASCII file). Make sure to add the Temperature channel to the list of Channels To Save and write out frame 19. Then open in a Text Editor like Notepad and explore the values - are the Temperature values 0.0 or positive numbers? What numbers do you get?
As I explained already:
*If a material is assigned to the FumeFX and there is NO Emission override, the FumeFX will render the Material, with shadows.
*If the material assigned has the Gradient Ramp in its Diffuse channel, since no UVs are generated at this point, the Blue color will render as Diffuse, with shadows.
*If the Override Emission and Use Emission are on, the map or color of the Override will cause all particles to be 100% self-illuminated, thus overriding most of the shadows look (shadows are particles with no light, but shadows with 100% blue self-illumination are not shadows anymore )
*If you have the Gradient in the Emission Override AND the UV Generation is correct (assuming the Temperature channel has valid data and is scaled in the right way), the Gradient should map to the particles and produce the various colors you expect. So at this point, I would use this approach and try to figure out what the content of the Temperature channel really is…
Hi Bobo,
thank you very much for the reply… sorry!
I tried other tests.
In the first test FumefX emitter temperature was 500, but the color was completely blue, with no gradient (see the attached files .csv the temperature is the last value on the right of each line??).
Then I tried to raise emitter temperature up to 2000, and you can see more clearly the gradient: so the problem is surely the temperature of FumefX.
Why can you see more clearly the gradient if you change the multiplier into a LOWER value (0.001)?
Two questions more.
Why the hottest part (the flame) appears blue and not red (like in your test)?
Why if emission is off you can see wire color of FumefX grid and you can’t see the gradient anymore?
Thank you very much again for your help, Bobo! CSV_FirstTest_frame12_13.rar (1.08 MB)
Ok, 500 * 0.03 = 15 which clamped between 0 and 1 is 1. BUT if you look closer into the tutorial’s screenshot, you will notice I was not clamping to 1.0 but to 0.99.
This is because when the U value goes to 1.0, the Gradient Ramp’s Tiling warps over and becomes 0.0 again, producing blue instead of red. Change your flow to use 0.99 and your color will be right (red). If your max. temperature is around 2000, you should divide the temperature by 2000.0 (or multiply by 0.0005) to get it into the right range.
When you disable Emission, no color is generated and the FumeFX renders in its default (wireframe) color.
You can move the Gradient Map to the Color Override if you want the color of the FumeFX and not the Emission to be set.
Isn’t it obvious?
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