Object with mask modifier emits particles mostly from object center #32109

New Issue

Alex Faiad · 2012-07-15T13:48:21+02:00

Alex Faiad commented

2012-07-15 13:48:21 +02:00

%%%PROBLEM:
When an object has a mask modifier and a particle system, most or all particles will be emitted from its center in a single line. This also happens with other modifiers in other situations, but I was not able to predict why and how they would happen. But with the mask modifier the problem is sure to happen.

TO REPLICATE:
Create a plane, subdivide it, create a vertex group and insert one or more faces on it, create a mask modifier with this vertex group selected, create the particle system and run the simulation.

WHAT WAS EXPECTED:
The particles should emit only from the non masked faces, and no particle should be emited from the object center.

SYSTEM:
blender 2.63 r46461
Linux Mint 64 bits (also tested on windows XP)
Geforce gtx 460 and other nvidia cards tested.%%%

%%%PROBLEM: When an object has a mask modifier and a particle system, most or all particles will be emitted from its center in a single line. This also happens with other modifiers in other situations, but I was not able to predict why and how they would happen. But with the mask modifier the problem is sure to happen. TO REPLICATE: Create a plane, subdivide it, create a vertex group and insert one or more faces on it, create a mask modifier with this vertex group selected, create the particle system and run the simulation. WHAT WAS EXPECTED: The particles should emit only from the non masked faces, and no particle should be emited from the object center. SYSTEM: blender 2.63 r46461 Linux Mint 64 bits (also tested on windows XP) Geforce gtx 460 and other nvidia cards tested.%%%

Alex Faiad commented

2012-07-15 13:48:21 +02:00

Changed status to: 'Open'

Danny McGrath commented

2012-07-15 15:21:46 +02:00

%%%I tried recreate my own scene (haven't tried your blend) from your instructions alone here in linux and ran into the exact problem you mention.

While playing around, I noticed that if I mask off, say 2 or 3 faces on one side, and then use grid distribution for the psys, the particles seem to emit in lines that start on the mesh, but keep going past the part that should be masked, clearly creating more particles than it should.

I am thinking that for emitters with a mask mod before the psys, that the line going straight down in this case, are just all of these "extra" particles that should have been masked somehow shooting out of the origin since they don't know where they should be coming out from. Either way, sounds like a minor bug. :)

Also, I noticed that it doesn't appear to happen for hair particles (although in reality, it could just be drawing a few hundred hairs on the same exact origin point, and thus not visible).%%%

%%%I tried recreate my own scene (haven't tried your blend) from your instructions alone here in linux and ran into the exact problem you mention. While playing around, I noticed that if I mask off, say 2 or 3 faces on one side, and then use grid distribution for the psys, the particles seem to emit in lines that start on the mesh, but keep going past the part that should be masked, clearly creating more particles than it should. I am thinking that for emitters with a mask mod before the psys, that the line going straight down in this case, are just all of these "extra" particles that should have been masked somehow shooting out of the origin since they don't know where they should be coming out from. Either way, sounds like a minor bug. :) Also, I noticed that it doesn't appear to happen for hair particles (although in reality, it could just be drawing a few hundred hairs on the same exact origin point, and thus not visible).%%%

Sergey Sharybin commented

2012-07-16 15:01:52 +02:00

%%%Would investigate this issue.%%%

Alex Faiad commented

2012-07-16 16:05:42 +02:00

%%%Thanks =D

I would like to point out that this happens with many other modifiers, including situations where, just using the subsurf modifier on a mesh the same happened. But sometimes it does not happen.

Maybe solving the source of the problem with the mask modifier would solve it with all other modifiers. %%%

%%%Thanks =D I would like to point out that this happens with many other modifiers, including situations where, just using the subsurf modifier on a mesh the same happened. But sometimes it does not happen. Maybe solving the source of the problem with the mask modifier would solve it with all other modifiers. %%%

Campbell Barton commented

2012-07-24 02:02:30 +02:00

%%%don't think this is a bug, particles expect the original faces to exist.

while this could be supported - I think this is just limitation in design and not a bug.%%%

%%%don't think this is a bug, particles expect the original faces to exist. while this could be supported - I think this is just limitation in design and not a bug.%%%

Sergey Sharybin commented

2012-07-26 11:58:37 +02:00

%%%Checked on code and TODO list -- it's known design limitation (see constructive modifiers section http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Tools#Particles)

Would close the report as TODO.%%%

%%%Checked on code and TODO list -- it's known design limitation (see constructive modifiers section http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Tools#Particles) Would close the report as TODO.%%%

Sergey Sharybin commented

2012-07-26 11:58:38 +02:00

Changed status from 'Open' to: 'Archived'

Sergey Sharybin closed this issue

2012-07-26 11:58:38 +02:00

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Object with mask modifier emits particles mostly from object center #32109