Metaballs in a particle system fails to render when particle system is not set to display Render #25794

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Patrik Andersson · 2011-01-25T13:48:49+01:00

Patrik Andersson commented

2011-01-25 13:48:49 +01:00

%%%Metaballs in a particle system fails to render when particle system is not set to display Render.

How to recreate:
Create a particle system, let it duplicate a metaball, you have to increase the size of the metaball/particle to make it render.
If you change the particle system's display setting to display anything else than Render, render will fail.
The metaball has to be in a visible renderlayer as well, which you have to hide in some way.

I have attached a scene with the setup so it is easy to confirm.
No problems with an ordinary mesh, see .blend file.

Blender 2.56.0
r33949

MacOSX 10.6.6%%%

%%%Metaballs in a particle system fails to render when particle system is not set to display Render. How to recreate: Create a particle system, let it duplicate a metaball, you have to increase the size of the metaball/particle to make it render. If you change the particle system's display setting to display anything else than Render, render will fail. The metaball has to be in a visible renderlayer as well, which you have to hide in some way. I have attached a scene with the setup so it is easy to confirm. No problems with an ordinary mesh, see .blend file. Blender 2.56.0 r33949 MacOSX 10.6.6%%%

Patrik Andersson commented

2011-01-25 13:48:49 +01:00

Changed status to: 'Open'

Moolah Nasreddin commented

2011-01-25 15:29:58 +01:00

%%%win32, r34231 - looks like the same problem.

Also I want to add that if you have a very big particle ammount (I tried with 5000) in 3dView (while being set to display render which is metaball) - you will have to wait a long time (may be about minute or more) while changing, deleting or assigning a new material to a metaball. It's very unwanted.%%%

%%%win32, r34231 - looks like the same problem. Also I want to add that if you have a very big particle ammount (I tried with 5000) in 3dView (while being set to display render which is metaball) - you will have to wait a long time (may be about minute or more) while changing, deleting or assigning a new material to a metaball. It's very unwanted.%%%

Ton Roosendaal commented

2011-01-25 17:16:41 +01:00

%%%I think you mix up particle "display" and "render" options with the metaball options itself. Metaballs just have different behaviour than simple meshes for duplication.
Select the original ball and check the properties for metaball polygonizing. It's on a default that might not work for you.

Anyway, loading your file and press F12 shows me the duplicate balls, but they're not nice. Just change the metaball "resolution" settings for nice visuals.

The fact the original meta has to be in the same layer as the duplicates is a part of the spec, metaballs work based on layers you know (that way you can make multiple metaball systems that don't work with each other).%%%

%%%I think you mix up particle "display" and "render" options with the metaball options itself. Metaballs just have different behaviour than simple meshes for duplication. Select the original ball and check the properties for metaball polygonizing. It's on a default that might not work for you. Anyway, loading your file and press F12 shows me the duplicate balls, but they're not nice. Just change the metaball "resolution" settings for nice visuals. The fact the original meta has to be in the same layer as the duplicates is a part of the spec, metaballs work based on layers you know (that way you can make multiple metaball systems that don't work with each other).%%%

Patrik Andersson commented

2011-01-25 17:56:17 +01:00

%%%Hm... did you try to change the settings? Try to set the display option to point instead of render in the particle system. I apparently left it with the display option render on - sorry for that.

Ok, I'm not into the specs of metaballs, but if they have to be in the same layer - I can live with that. I can hide the "original" ball behind the camera, or something else:)

My point is, if you chose to use a metaball as a particle object you would save a lot of time/calculation by having the particles displayed as points instead of metaballs.
When you go rendering, the calculation of the metasystem can begin, or when you chose to display as Render.

The origin of the dilemma appeared when I try to do a fine fluid simulation, and choose to use like 10000 particles as metaballs, to create a liquid when the particles are close enough to each other and when not create like a spray effect. Having all metaballs displayed at the same time slows down the system very much, therefor I selected display points instead but then when I render that the metaballs wasn't there as predicted.

Are you with me, Ton?%%%

%%%Hm... did you try to change the settings? Try to set the display option to point instead of render in the particle system. I apparently left it with the display option render on - sorry for that. Ok, I'm not into the specs of metaballs, but if they have to be in the same layer - I can live with that. I can hide the "original" ball behind the camera, or something else:) My point is, if you chose to use a metaball as a particle object you would save a lot of time/calculation by having the particles displayed as points instead of metaballs. When you go rendering, the calculation of the metasystem can begin, or when you chose to display as Render. The origin of the dilemma appeared when I try to do a fine fluid simulation, and choose to use like 10000 particles as metaballs, to create a liquid when the particles are close enough to each other and when not create like a spray effect. Having all metaballs displayed at the same time slows down the system very much, therefor I selected display points instead but then when I render that the metaballs wasn't there as predicted. Are you with me, Ton?%%%

Patrik Andersson commented

2011-01-25 17:58:35 +01:00

%%%I test it with the latest Mac OS X build r34486 and the issue still remains.%%%

Ton Roosendaal commented

2011-01-25 17:59:10 +01:00

%%%Ahh, sorry didn't know about this type of display :)
Will ask Janne to check it.%%%

%%%Ahh, sorry didn't know about this type of display :) Will ask Janne to check it.%%%

Patrik Andersson commented

2011-01-25 18:07:25 +01:00

%%%Thanks :)%%%

Janne Karhu commented

2011-01-26 12:33:18 +01:00

%%%The problem is that with metaballs (ancient code!) the dupliobjects have to be created multiple times. Particles use the render settings only when the actual particle object is handled and clear the render settings after that (has to be done so that objects can duplicate the particle object and create new render data for those duplicates). As the particle render settings are already cleared when metaballs are created they don't get created at all.

The only solution I can think of would be to call dupli_render_particle_set(...,1) before object_duplilist(...) in the metaball function next_object(...), and dupli_render_particle_set(...,0) after it as done in the normal object duplication code, but as the dupliobject functions aren't inside render code this would create big amounts of duplicated code or many bad level calls, so I'd rather wait for the metaball code to be cleaned up as this is certainly not the only problem with them.

Closing this as a todo item for now and adding notes to the wiki todo page http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Tools#Particles.2FHair.%%%

%%%The problem is that with metaballs (ancient code!) the dupliobjects have to be created multiple times. Particles use the render settings only when the actual particle object is handled and clear the render settings after that (has to be done so that objects can duplicate the particle object and create new render data for those duplicates). As the particle render settings are already cleared when metaballs are created they don't get created at all. The only solution I can think of would be to call dupli_render_particle_set(...,1) before object_duplilist(...) in the metaball function next_object(...), and dupli_render_particle_set(...,0) after it as done in the normal object duplication code, but as the dupliobject functions aren't inside render code this would create big amounts of duplicated code or many bad level calls, so I'd rather wait for the metaball code to be cleaned up as this is certainly not the only problem with them. Closing this as a todo item for now and adding notes to the wiki todo page http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Tools#Particles.2FHair.%%%

Janne Karhu commented

2011-01-26 12:33:18 +01:00

Changed status from 'Open' to: 'Archived'

Janne Karhu closed this issue

2011-01-26 12:33:18 +01:00

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Metaballs in a particle system fails to render when particle system is not set to display Render #25794