Xfrog, Opacity and Render Times

[jmottle]

I've been doing a bit of R&D for an upcoming project. The shot calls for a very relistic forground tree that will be in the animation. I want to use an Xfrog tree so I imported one of their trees (using one of their max files, not an imported Xfrog file). The default tree comes in with a 10 slot multi-sub-materal that looks like this:

Tree
---ID 1 Bark
---ID 2 Leaf 1
------Diffuse
---------RGB Tint
------------Leaf TIFF file
------Bump
---------Leaf TIFF file
------Opacity
---------Leaf TIFF file (Mono Channel: Alpha, RGB Channel: RGB, Alpha
Source: None)
---ID 3 Leaf 2
---ID 4 Leaf 3..........


To render the tree with the standard max material takes about 15min with just skylight and a 'very low' IM setting. I've been reading all the tree and Xfrog thread on the forum and they all indicate that using vray material opacity would be faster. I used the global convert all materials to Vray materials and tried the render again. The render time shot up to over 3 hours!

I did a bit more reading and it was suggested to use the refraction slot for opacity however I have yet to be able to get the same result as using the Opacity slot. The best I can do results in not only the leaf being cut out, but the leaf itself being made semi trasnparent.

So, what IS the best way to render an Xfrog tree so that the render time is not 3 hours using a Vray material, Why is this happneing?

[gitano_anton]

Jeff, try this:

This is the process that i´ve used to texture Speedtree2 models.
I suppose that Xfrog models are made with billboard.
Use a blend mat.

1st slot: Vray material wrapper with matte and shadow enabled.
2nd slot: Vray material with only the bitmap in the diffuse slot.
3rd slot: Bitmap with the same bitmap ( only the alpha channel ) inverted,
invisible is white.
Send me an answer if it works.
I like your web.

[yage]

well, i did it this way:
http://www.chaoticdimension.com/foru...pic.php?t=8601

it worked out very fine - rendering time wasn't that high as expected.

[jmottle]

1st slot: Vray material wrapper with matte and shadow enabled.
2nd slot: Vray material with only the bitmap in the diffuse slot.
3rd slot: Bitmap with the same bitmap ( only the alpha channel ) inverted,
invisible is white.
Send me an answer if it works.

Does not seems to work. Not sure if I've misinturpeted what you are explaining.

[yage]

send me your materials, i gonna have a look.
or just read my settings again (link posted above)

[jmottle]

http://www.cgarchitect.com/test/leaf.zip

The Zip contains the two materials. The one blend material you explained and the Vray Opacity material I was trying to get working. The really od thing about the latter material is that I can not reproduce it in another slot despite the settings being identical.

[Infrared digital]

I just got some Xfrog stuff but, cannot find a way of exporting the optimised Xfrog models from Tune to Max 6.

Has anyone done this - the email for the people @ Xfrog is down presently.

Thanks

N

[Da_elf]

in the new versions of vray there is an opacity map in the vray material. its quite fast

[Frances]

Da_elf wrote: in the new versions of vray there is an opacity map in the vray material. its quite fast

Hi Da_elf,

That is good news. Is it available in the public beta? Lots to look forward to in 1.5.

[Da_elf]

as far as i know its in the 1.45.70 version available to the public.

[jmottle]

I was using the public 1.45.70 beta and it definetly was not fast. I ended up using Onyx trees in the end, but I did use standard materials with an opacity map and it was quite fast.

[paulison]

is there any advantage to changing the standard Xfrog materials?

Im trying a few trees out in a current project and although slow, they look good so i'm happy. If there is a large speed increase by changing the materials to vray, i'll convert them all.

Is there a tutorial somewhere on how to convert the xfrog materials to vray? i'm having troubles figuring out what needs done.

Lastly, is there some other reason not to just import the xfrog trees? like a technical reason maybee effecting stability or rendering outcomes?

[schroeder]

Hi Jeff,

I typically use a b/w jpeg to control the opacity. Dropping that in the opacity slot for me eliminated the halo effect and helped render times, rather than relying on the alpha in the tif files.

Just as reference, I just did an image with 30 xfrog trees from one of the libraries, with over 10million polys using vrayproxy objects, and the render time was about 7 hours. With medium IR and default lightmap settings.

[dennis]

i dont know if it has been covered but here goes.

If you use the same .tif bitmap for opacity as for diffuse, change, in bitmap param. rollout > RGB channel output, from RGB to ALPHA as grey. You can aswell ( if you dare ) set filtering to none, this effectevly cut render time in half.

The above changes is only for the opacity slot _not_ the diffuse so dont instace the map but rather copy