Particles won't bake and particles won't render

Hi all,

Am at wits end. Have a scene with a laser cutter (yes very cliched, I know). Laser head follows a text curve and an emitter object follows the laser.

I have five emitter objects each with it’s own particle sytems. One for each of the letters it is cutting out (the metal object, camera changes and so forth are in another file). The letters go in the order M e y m s

  1. Alt-A to generate the cache results in M appearing as the red highlight on the timeline, no others appear. The caches generate fine for all letters EXCEPT the second one (e). I’ve tried deleting it, re-adding it, baking it, saving cache to disk, releasing all bakes, closing, saving, reopening… nothing works. ARRGGHH!

  2. Somehow the actual objects have stopped rendering. I bulked up the size of the M particle to demonstrate that when the render occurs, the emit value works fine, but the actual particle (object: Spark particle) does not. I removed the transperancy and replaced with a diffuse in case that was the problem. Nope. I even replaced the duplication object with a plain cube (object: Test cube) and it still refused to appear. I tried adding in render: unborn and died, double checked that the particle render toggle was checked in the modifiers panel, tried modifing the material index (though this shouldn’t make a difference as it is using the material of the object) but still nothing appeared. There are otehr lights in the scene so it’s not just a case of no light. I duplicated from scratch the particle system, objects and cycles material in a new file and it worked fine but cannot for the life of me work out what I have changed in this file to make the objects dissapear…

I’ve spent a couple of hours scouring various help sites looking for answers without luck. I know that this is probably a case of user error (99% of the time it is) and I also know that as soon as someone finds the problem I’m going to be smacking myself on the side of the head yelling you you idiot!:slight_smile:

Having a little trouble attaching the file - will keep trying. Thank you in advance for anyone who has a chance to look at this post and/or solve the problem.

 - andrew

BTW: I also checked that camera ray visibility was on; swapped the order of the particle/armature modifier; deleted the armature modifier without the particle re-appearing. Tried CPU and GPU compute. Also looked at the spark particle material in the 2.66 RC1 cycles preview and it showed up in the preview panel just fine.

Windows 7
i7 8xcore
Blender 2.65.0 r53189
NVIDIA GeForce 540M

  • whack *

Yes the camera ray visibility was turned on for the particle - but not the emitter!

At some point in the past, for some totally not-apparent reason I turned it off. When I duplicated each of the emitters the camera ray visibility was set to off.

One of the dangers of picking up work a month or so old…

The bake/cache problems don’t seem to be interfering with the actual render (going to test overnight) through they could be related to the weight painting. As part of the hunting of the reason the particles were missing I created a new particle system and manually copied and tested each setting one by one from the first of the “broken” ones. The new system didn’t interfer with the caching display of the old system until I started weight painting…

Anyway, enough frustration for one day.

Hopefully this will help someone else in the future…

  • andrew