Surface population w/ default Xfrog trees.

Started by chadkruger, November 12, 2007, 09:22:12 PM

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chadkruger

Hey,

Have a problem using the Xfrog trees that came with the Technology Preview.  I set them up using a population.  However when I changed the surface on the leaves (specifically, reducing the opacity to 0 to create leaveless trees), not all the trees are affected.  Is this a known bug and is there a workaround for this?  Any help appreciated.

bigben

Do you still have an opacity image/function assigned as well?

It's prbably better to remove the leaves altogether.
http://forums.planetside.co.uk/index.php?topic=2680.msg27259#msg27259

chadkruger

Opacity/Image function...not sure what that means.  I try to avoid the nodes, if at all possible.  But the only modification I did to the tree was reduce the opacity of the leaves, which worked great for at least one member of the population, just not the rest.  Remove the leaves?  Sure, is that possible within Terragen or do I need one of those 'other' programs that are not so user friendly?

bigben

Any change you make to the reference object of a population should be applied to the whole population. you didn't accidentally add a single tree and a population?

Yes removing them requires another program. The notes in the linked post above refer to PoseRay. This is a very handy tool for helping with objects in TG2... maybe some PoseRay for TG2 tutorials are in order?

Oshyan

If the change is only affecting some of the leaves perhaps there are multiple leaf groups? Either that or, like Ben said, perhaps multiple source tree objects/populations occupying the same space. It's really rather hard to say without A: more details about your scene (or an example .tgd file) and/or B: an image showing the problem in a render.

- Oshyan

chadkruger

#5
Alright.  I think I've found the problem after a little experimentation in reproducing the problem from an earlier file.  At the very least, I've uncovered a new error.  The file I was having trouble with is the fogged version, which is the effect I was going for.  In the second file, the leaves are no longer visible; the only difference being a reduced haze density.  It seems as though the 'visibility' of the fog is making the 'invisibility' of the leaves void somehow.  It's probably a flaw in the coding that calculates the value of the opacity of an invisible object and the saturated visibilty of the atmosphere.  Or something in the opacity setting that prevents it from being set to absolute zero, making it shadowed nonetheless under certain conditions that would give us this outline.   

Addressing the other concerns the big tree on the right is alone and not included in population; its the ones in the background that are being addressed here.

bigben

There certainly seems to be a distance component to it. If you remove the leaves in PoseRay you could also smooth the normals of the branches at the same time.  ;)

bobbystahr

I have also noticed this but had run into a similar problem in Imagine with Fog...only the closer trees had the correct opacity/invisibility. The best way to have a leafless tree is in fact to disable the leaf groups in PoseRay as suggested by bigben.. ...
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist

Matt

Interesting find! It's quite probable that the opacity generated by the atmosphere shaders is confusing the part of the renderer that decides whether to render something opaque or invisible. If so, that would affect opacity maps too. I will look into it.

Matt
Just because milk is white doesn't mean that clouds are made of milk.