View Full Version : Dodgy Clouds Outlines

06 June 2007, 11:48 AM
Hello everybody im a noob ere so be nice =) im trying to render this large enviroment... with a sphere of enviroment fog and blobby clouds inside.... you can see the problem, theres an outline underneath the clouds which appears regardless of raytracing/rendering quality

Any thoughts?

On another note... which aspects of that scene do you think would be worth baking to speed up rendering? ATM its about 6 mins a frame


06 June 2007, 10:11 PM
considering the size of the scene which seems large. 6 mins isn't bad. Using Mental Ray etc. would take way, way longer. Anyways, see if the line is being caused by some sort of geomoetry. that's what it looks like. Maybe that is what's casting the round crisp shadow on the ground?? Possibly trying to increase your Far clip plane in your camera settings to 1,000,000.? Hope this helps.

06 June 2007, 06:35 PM
The line on th ground is a shadow of the dome... thats all good. I tried increasing th camera clipping plane... no luck. Im pretty sure th line on the clouds is something to do with th alpha map, its similar to the outlines you get on shadows cast with raytracing, almost transparent but not quite. The solution to that was turning 'shadow attentuation' in the textures mental ray attributes to zero, but the 3D cloud texture doesnt have that tab

That scene was rendered in mental ray btw....

06 June 2007, 10:39 PM
Well 6 min for mental ray is good (in my opinion). so what exactly is the dome used for? it makes sense to me that what you are seeing is the dome intersecting with the environment fog where its geometry ends. its curved like a hemisphere and you are using one to cast a shadow correct?? If there is any geometry (dome) where that line is occuring chage the render stats of the object. Uncheck Primary visability in the attribute editor.

06 June 2007, 01:53 PM
The dome is part of the scene... It does look like the line is where the fog intersects it but it still appears if i turn th dome off (by make its layer invisible). The fog is volume fog applied to a sphere btw.. not enviroment fog like i said. Its almost definatly the clouds because when rendered from above the outlines are around each particle (blobby cloud) object.

thanks btw.. ive posted this on 3 forums are ur the only person whos had any ideas


HURRAH!!! got it sorted. I put a particle very far away in all directions so its group bounding box doesnt intersect th fog.... its always the simplest answer =)

06 June 2007, 05:50 PM
Glad you got it worked out :thumbsup: That's what I tell everyone, its usually just something simple. goodluck with everything. Later

CGTalk Moderation
06 June 2007, 05:50 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.