smoke camera angel seems fine in preview but totally different view after render

I have some problems with smoke simulation

first, the preview smoke effect is gone, when I played around a little while, I tried to restart the laptop, use the newest build in trunk, but nothing works. It just gone, I can only see few particles bounce to different places on my plane, but no smoke goes out.


After I baked it, I can see the smoke now, so the problem is sort of solved but still a bug I believe.

the second problem is , after I changed the camera and rendered. It looks totally different angel of the smoke, no matter how I change the camera, it stays.

check my pictures in blender before render



and after render

I am using blender 2.59 and macos 10.7.1

So, these is a problem with the smoke simulator some of us encounter. It turns out that the problem is a simple texturing problem. You see blender uses the voxel data like a texture on the cube. To work the white parts of the voxel data (the smoke you baked) have to be in the right spot on the cube. THe problem comes in when blender doesn’t take into transformations of the cube before and during the simulation so… You have to manually adjust the smoke texture coordinates. (NOT FUN!) You need to go into the texture panel and for the voxel data texture you need to adjust the position settings under mapping. Adjust the x,y,and z values (seperatly) in small increments and render to see what you need to do to get the smoke looking right. Well, good luck with that.

Ok, It seems I found a way to reproduce this

new a default scene
use the default cube to be the smoke domain
g+z+1 move the cube to the floor level
ctrl+alt+c set the origin to 3d cursor
s scale the cube a little bit
this should cause the problem…thanks for gat19g
shift+a add a mesh-> plane
select plane and move up z a little bit
use the plane as flow ( no smoke preview here )
bake it, after done , I can see the some preview



f12 render it, can’t see any thing, cuz cube didn’t use volume material and texture is
not voxel data
change the domain cube material to volume and texture to voxel data and some other


and render it again the result is different, please notice the smoke postion is changed. even I rebake it, it remains that way

thanks so much for you reply. I know where is the problem, if I reset the origin point to the center, the smoke looks right. It is really as you said, it’s a texturing problem - -, just as other texturing did! The smoke is a texture, that sounds a little bit unnatural to me, but I’ ll tried to adapt to it:D

I don’t know why they can make the preview right but not the final result, It’s a bug or some reason behind this?

Yea, I learned this the hard way, I spent hours on different projects messing around with the smoke simulator and voxel data. Mostly because it still needs help and is not up to things like FX for Maya. Once you get used to it is becomes a little less frustrating :wink: