Heat wave replication


(Idgas) #1

OK question, and i did a search already but couldn’t find anything. You know how when there is a source of heat (lava or fire) it emits a heat wave. How can i replicate that in blender. Anyone have an idea???


(z3r0 d) #2

at the moment I have not been able to try this… Maybe I will soon…

(oh, and I don’t know if giving away my thoughts on this right now is a good idea)

The heat waves are caused by the different temperatures in the air bending light differently.

Abstract:
To simulate it, you should have the image be warped.

In detail: (Hopefully will make sense)
1 or more plane with normal-modifying stucci (or cloud?) texture that moves upward.
On top of this an environment map, calculated from the pov of the camera, with the sizes set to match (closely) the background.
I would imagine that above this there should be a stencil texture that limits the environment map, or the normal modification to allow for differences in heat effect.

I think I shall try to run blender and find a way.

I may post later


(z3r0 d) #3

After I remove blender from a lab computer, I realize what I was doing wrong…

Ok, so this will NOT be easy, but I will tell you what I figured out.

I was trying to have an environment map reflection mapped onto a plane. In order to have this line up with the camera:
A) There must be an empty at the camera location, for env-map calculation
B) The plane must be perpendicular to the plane of the camera (track-to maybe)
C) sizeZ (for the env map) must be set to -1 (material buttons)
D) the plane the env-map is on must be in a layer that is not rendered in the environment map (in texture buttons)

While playing I forgot B.

Well, anyways, this will not be something for people who don’t understand how textures work in blender.

Ok, higer up (as in calculated before the env map) in the texture channels there should be something that at least modifies the normals to simulate the bending. Above that there should probably be something that makes the normals not modifiable outside of an area… So that the edge of the heat wave is not the edge of the plane. I don’t know how this would be done in a way that would not effect the area where the env-map is drawn.

Idea, follows the texture channels in order
Environment map (with settings as mentioned above)
Image with alpha channel for outside of the area, in stencil mode. With color (col) turned off
Normal editing area
Duplicate of Environment map.

The latter two should be drawn in the area where the (stenciled) image does not effect if my memory holds correct.

I am not allowed to install blender on this computer (although I have never seen them enforce this rule), so I could not try it.


(Idgas) #4

cool sounds difficult, GREAT!!! I’ll give it a try and see what happens.


(ray_theway) #5

Look at this tut using the warp plugin to simulate atmospheric distortion. This tutorial is specific to bullet trails, but the skill can be applied easily to other kinds of heat waves (just experiment). You can also modify the sequence editor part to not have to save the image each time.

http://www.stormpages.com/madcow/Warp_tutorial/warp_tute1.html


(Idgas) #6

thats what i wanted. Only prob is when i select the warp.dll blender tells me no plugin. what happend???


(z3r0 d) #7

I never really was satisfied with the way blender does plugins because I can’t guarntee I will be running the same os the next day…

umm, what I have done (I would imagine is more complex) allows an empty to control the motion of the bending of the image…

It is NOT a plugin. :), though python may help it some.

See an mpeg (which I may delete in a week, or longer) at http://home.earthlink.net/~nwinters99/BlenderStuff/heatWave.mpg (1.22Mb Ligos mpeg1) Seems to work now

the blend http://mywebpage.netscape.com/YinYangEvilSane/BlenderStuff/HeatWave/HeatWave1.blend (59k)

and an image
http://mywebpage.netscape.com/YinYangEvilSane/BlenderStuff/HeatWave/HeatWave.jpg
(49?k)
in the image the fine white lines on the icosophere, and the thicker ones (which are bent) is sorta a defect. Look at the .blend too see why.

(I don’t care if it is now irrelevant, it was fun)