There is a known bug with motion blur combined with rigid body physics in 2.72, some frames just don’t render right. I know that for that issue rendering with 2.71 works. It’s possible this is a different version of that same physics/motion blur bug. Give 2.71 a shot, at the very least it’s a painless try.
Hmm, back to drawing board. If you want to post the packed blend we can look at it, if it’s not something you can share publicly you could pm it.
I wouldn’t file a bug report yet, until we rule out settings.
Also I am not 100% what the issue is. You say the middle image is blurred, but that it to be expected from motion blur. Also have you actually rendered it out out to video and watched it. Sometimes still frames of blur can look odd, but they look perfect when viewed as video. Perhaps elaborate a little on the issue.
Yes, I did not explain as well as I could I guess! I will see if I can get the .blend to a manageble size. The only thing you really would need is the chains and lightning etc.
I have watched it after I rendered it out to a video. It’s actually more noticeble then.
The right chain at the middle picture (there’s more frames with the same problem) gets like “super motion blur” at only a few selected frames. Same frames every time I re-render. As you can see, the difference in the position of the chain is not at all much between the frames.
If it would be motion blur, the left would also look like that.
But the problem is only visible when having motion blur, so I’m a bit confused of what the problem could be.
Maybe blurred is the wrong word to choose, it gets very transparent.
Hard to say. I’m a bit puzzled, you say the chain has a curve modifier, that makes sense, but then you say the curve is somehow parented to a cloth sim, that I’m not visualizing. All I can think of is that the curve has empty hooks, and the hooks are vertex parented to 3 verts on a cloth sim mesh. It seems unusual. Dropbox a simplified version.
i have kind of the same problem. it’s the curve deform modifier that causes the motion blur to blur in the wrong direction.
i have a tube that follows and deforms along a curve, and the motion blur uses the direction of the tube as if has not the modifier applied.
You are correct. The curve has empty hooks that is parented to the vertex on a clot sim. It was the best alternative I could come up with my basic knowledge of blender. I will upload a simplified version today!
Yea this sucks. I’ve just run into this issue on one of my own projects as well. Only thing that seems to work is I wrote a script that bakes the object’s translation and rotation data into animation curves, and disables the rigid bodies (mine uses rigid bodies…). It’s really slow though… (100 frame animation (*10 sub-steps per frame) with about 2,000 objects takes a good 5 minutes to “bake”)
This method will only work if your chain is made up of links, and each link is it’s own object. (ie it won’t work if the chain is being deformed). Also, just to be safe, make a backup of your scene. If this is the case, I’d be happy to post the code here.