i have a set of 3 emitters using the same particle settings, and doing what they are supposed to. However, when the scene is rendered, some times “phantom” particles appear in the same pattern as the particles that are supposed to be there in a different location. The thing that makes this soooo annoying is that these phantom particles dont show in the 3D view port. They only show in the render. Here are some pics to illustrate this:
Here you see the 3D viewport. (no phantom particles in sight):
(i cant upload the blend file because it is too large (6 MBs). I have tried to deleating everything i can think of including objects, free all bakes, materials etc.)
I hope media fire is ok: http://www.mediafire.com/?qzdsgd4rbebxx53
the phantom particle appear randomly over any of the 500 frames. i have found them anywhere in the range of 136-295.
Sorry didn’t see link… Yeah got it ok… if you reduce particles to 1 its 530k … with a note to up it to 50k particles … anyhow… rendered it out no phantom particles on RHS for me so dunno.
the phantom particles dont show up on any particular frame. It apeers to be random to a degree. Try taking a more renders. I found them anywhere from frame 136 - 295. I tried it on two different computers (pc and mac) and i could consistently reproduce the issue.
Also, i dont know what RHS is… sorry. still kinda new to blender.
I reeeeeeeeeaaaaaly need help on this guys. This problem happens frequently on a much larger scale on many of my projects.
Yeah I rendered the animation albeit at 25% size… no phantoms… however your phantom particles do look like the emitter object … you could try unchecking emitter in the Render panel of the particles menu.
thanks, but no dice batfinger. i still found the phantom particles.
Try letting the animation run to around 100. Then let the frames go by 10 at a time and take a render every 10 frames. I am almost positive you will see them if you do that.
Also, what do you mean by “25% size”? Maybe that is why you cant see them?
Something weird going on. I rendered frames 100-300 at 50% and did not see any artifacts; I re-rendered at 100% and was getting artifacts on all frames. I cleared the frames in memory (select and then de-select Quick Cache) and the artifacts disappeared and did not come back. You could try clearing the frames in memory and see if that helps.
I tried clearing the the frames in memory but i still found the phantom particles/artifacts. It took me a lot longer to find them but sure enough, on frame 366, they showed.
I dont understand how you are testing this though. What are these percentages (50, 100%) you mentioned? if it has to do with taking animation renders, that is NOT what i am doing. I am taking still to see these artifacts. Also, at no point did i see artifacts on all frames. Maybe post some pics to help me understand? You think this might be a bug?
Shrug… just dont get them… Using 2.56.0 r344545M. The artifacts on your pic sure look like the emitter for leftmost firework has gone travelling. Have hardly used the compositor much maybe it’s something to do with that. Maybe render it without certain nodes to check.
Getting to where this black duck should hit the sack… got it rendering 100% … up to about 300 atm. no phantoms… Oh well.
You have chosen 1280x800 as your render size.(resolution). You can use the slider below to reduce that size when test rendering to make it quicker… in your pic below the phantoms are quite noticeable at a size that looks about 20%.
Rendered the animation as animation sequence png files 1 to 500 and as h264 avi which you had set… still no show for me.
Thats strange that you cannot reproduce the problem. Again, i am not using an animation to see the problem; just still renders. But i would think since you used pngs that it would not matter…
Well, thanks for helping batfinger. AlenK seemed to have found some oddities in this blend file so it appears that there is some kind of problem. Do you think i should try and submit it as a bug at blender.org so they can check the code?
Which version/revision number are you using gunforhire? Probably best to make sure you have the latest trunk from graphicall.org before submitting a bug report. And just realised i was using an OPT build when i tested hence the M i suppose.
2.56a
r34076
Im not doing anything fancy. I got blender straight from blender.org. I dont think i have ever been to graphicall.org. What do they do? What is a “trunk”?
It’s where you will find the most up to date blender builds. A trunk is an elephant’s noodly bit… or not completely sure . but i think it’s like this, there are development “branches” like say meshpaint… and until they are officially blender they aren’t considered the trunk… like you get from blender.org. The current trunk revision at graphicall.org is 34486.
so they are soon-to-be-official blender updates. they just have not been reviewed by blender.org. And i am assuming these revisions are basically bug fixes and other things that come with blender.org version updates. Is that accurate?
Something like that… when it’s decided that it’s 2.57worthy … there is a log that shows fixes/changes etc between revisions.
On your phantom problem are you baking the particle systems? Maybe scrubbing around is producing it. Do you get them when you render the whole animation?
I do scrub around to quickly see if anything goes out of the shot of the moving camera.
How do you bake the particles?
And yes, some times i see them from a full animation render. That is the whole problem. And it would not even be that bad if i could just see them in the 3D port before i render, but i dont know untill the final product if finished.
Ok, so months later, this issue is still bothering me. There was some confusion back then because the issue could not be consistently reproduced, which i realize makes troubleshooting pretty difficult. The download link will give you a blend file that i have consistently reproduced the issue on with 5 different computers, with different versions of blender, on both Windows and Mac.
Open the blend file and go to frame 5
press F12 to render
you should see the ghost particles similar to the what you see in pictures on the first post
if not, go another 5 frames and render
repeat until you see the ghost particles in the render
If you still cannot see the issue, here is a video that shows it:
Unless someone tells me otherwise, I will report this as a bug. The only reason i am posting this is to make sure this is a bug. I hate to bother the devs if it is my error.
