Rotation problem with particles

[Tofke]

Hi,

I'm trying to create realistic grass by using an emitter particle system. To start from, I have been using the blend file that voytov shared in one of the posts on the forum here (http://vray.cgdo.ru/forum/viewtopic....it=grass#p2988) - thanks for sharing that file by the way!
Whenever I'm rendering however, the resulting grass strands seem to be rotated about 90 degrees compared to what you see in Blender. I have been rotating the mesh used to create the particle system, as well as changing the "Initial Rotation" direction of the particle system. Both seem to have an influence on the orientation in which the particles are rendered, but I can't find any combination that renders the particles in a normal upright way like the grass should be.

Can anyone tell me how to render the particles in a normal upright way? I'm using a recent custom build with integrated V-Ray support (build 39889 - Windows 64bit) from graphicall.org and the V-Ray 2012 demo version.

Many thanks in advance,
Tofke

[voytov]

Re: Rotation problem with particles

Hi, there is still one efficient workaround: I rotate the base strand +90 deg over "Y" axis. Please note that the rotation was made in "edit mode" so the base strand object still has transformation (rotation) values 0,0,0 which is very important because of another bug which will increase rendering times if the initial particle object has any rotation values other than 0.
When you have this set you can still tweak any parameters of rotation inside emitter's config rollout..

Can't attach any screenshots because I get "Sorry, the board attachment quota has been reached" message.
So..
Sorry..
Good luck!

[d_ray]

Re: Rotation problem with particles

its a huge problem from blender.

plsu now random rotation is also not working. i hope they will fix it. or else we can not use particles

[Tofke]

Re: Rotation problem with particles

Hi voytov,

rotating the the base strands in "edit mode" around Y indeed did the trick for me. I still don't understand exactly what the logic behind it is, but at least I now have something that renders the way I want it and that gives me something to go from.

Thanks a lot!!
Tofke

[voytov]

Re: Rotation problem with particles

Hi,
good to hear that.
It was tested up to V2B version 2.56.
Yesterday I tried it for a moment on Graphicall 2.59 version but surprisingly it didn't solve the problem. So as you can see the system is not fully stable yet. I think that as version 2.60 appears, there will be a moment to ask Andrey to revise particles once more..

This strange behavior was also in blender 2.49. I have no idea why it was always kept unchanged..