Picture viewer render different then render within cinema 4d?

[Brian Jones]

picture viewer render vs editor render is often different if you have dynamics/particles/a number of other things going.
What particle system are you using?

[Chad Demoss]

all I have is a cloner cloning a bunch or spheres with a vibrate tag. I have a tracer object linked to the cloner and I am sweeping the tracer with a circle. the outcome is what I would expect inside cinema 4d. If you look at the image that has tentacles that is exactly what I want. I cant tell exactly what is going on by looking at the renders but it looks like either the sweep or tracer isn’t doing anything in the picture viewer render.

[Brian Jones]

The manual has many warnings about editor/picture viewer renderer differences but it would be good to see the scene file

[Chad Demoss]

thanks for your help.

12469_tentacles.c4d.zip

[Jim Scott]

Hi Chad,

From what I can determine (and this is somewhat of a guess derived from some experimentation) this has to do with the Shader effector and how its effects are computed and then rendered. I found that if you render out a movie, or image sequence, you will get the proper result for each frame. It seems to be something like how dynamics must be run to get the proper result. You can’t just select a frame and get the proper result without running the dynamics simulation. And apparently the Shader effector works similarly. Why the results from the Viewport don’t carry over to the Picture Viewer, I don’t know.

I’ll leave it to someone who is smarter than I am to explain why this is happening, but I couldn’t find any reference to it in the help section. And I’ll bet that Brian will probably have a better explanation.

[Brian Jones]

not much of a better explanation I think, Jim. What you said stands for a number of things in the main render window – only rendering all the frames will give you the results you expect. I think it has to do with Mograph effectors not really moving the clones except in ‘clone space’ but I don’t know the intricate details.
I do know with this setup if you turn off the vibrate tag (get rid of it) and let the clones move out under the effect of the effectors ☺ you get no trails at all in a picture viewer render since the clones haven’t really moved in the Tracer’s space (or something like that).
Also, you always play the timeline to get to a particular frame in the editor, I would guess, try jumping to a frame in the editor (just click on 50 in the timeline for example) — you get a mess the way it’s set up but that’s due to the Sweep having Constant Cross Section selected… deselect that and you get the same thing as in the Picture Viewer render, no trace if vibrate is deleted. If vibrate is there you get no traces in the editor but the same thing as before in the picture viewer – the spheres are out there with only a trace put there by the vibrate tag (I’m guessing).

[Chad Demoss]

Thanks very much for your help.

That makes sense to me, the tentacles are made from an animation so i guess it needs to run the animation. Although i’ve done still frames from animated sweeps, trails, particles etc… before without this issue. I guess its a combination of a bunch of things that is causing this.

[Steve Bentley]

Adding to both Brian and Jim’s comments, if you bounce around the timeline you will see that the effect becomes a real mess, instead of diminishing as you move the time marker to frames closer to zero, and increasing as you bounce to later frames, it just keeps adding up to a bigger and bigger blob. I think C4D does this (and this is related to your problem) because its a faster way to get a visual result and update the viewer, rather than recalculating from the start frame every time you change the time marker. So you can sometimes be looking at something that won’t actually render that way because it’s not been calculated from the beginning in a linear way. Simulations like this (and the tracer is technically a sim) need to “run in” as each consecutive frame is predicated on what has come before, all the way back to the beginning of time (this is the next Jurassic park sequel’s title by the way).
I know that doesn’t solve the problem but you could bake the effect and that way at least you would see what geometry you will get on every frame correctly and it will speed up the back and forth in the time line as you finesse shaders etc.

[Jim Scott]

Hi Steve,

I am familiar with baking dynamics, but how does one “bake the effect” as you mentioned? I was thinking along these same lines but don’t know how to go about it. A mograph cache tag on the cloner doesn’t seem to do it, but that’s all I could think of.

Thanks