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View Full Version : Soft reflected vegetation, leaves - hint



Sanchon
03-20-2015, 07:58 PM
I noticed that many of lightwavers and companies who makes vegetation objects for Lightwave using soft reflection for leaves but in the worst form. Soft ray-tracing for leaves, especially with instances ( grass, trees ) can be very slowly.

Here is a tip for make it much faster :

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As you see - Reflection Options for leaves is set to Backdrop Only. The fasted method of reflection - without raytracing. You can occluded it with occlusion node. I prefer occlusion node from Denis Pontonnier's DPkit, because you can drive quality independend from main shading samples :

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Angle : how much sharp reflection will be on the leaves

Very fast rendering for soft reflection on the leaves, grass without noticeable quality drop.

jwiede
03-20-2015, 08:25 PM
Seems like we could really use a "fast, very blurry reflection shading" option in std materials. Essentially the same as what we already have, but with reflection driven by simplified Schlick's + AmbOcc (as in your node flow) as an alternative to the ray-traced reflection models. Building by nodes obviously works, but seems like having it pre-configured as a "fastpath" setup would allow greater overall optimization capabilities (and allow avoid nodes altogether in many cases).

Put another way, if users wind up adding something like the above via nodes to most non-metallic surfaces in a render, seems easier just to offer it as a fundamental surface reflection option in the first place. For many non-complex surfaces, doing so would eliminate need for diving into nodes at all.

Just a thought.

vonpietro
03-20-2015, 09:43 PM
Do you have an example? and render times maybe? =)

djwaterman
03-21-2015, 01:04 AM
Can you explain the normal map going into a phong shader and then into the specular shading? Likewise I'm not understanding a normal map going into the ambient occlusion node (although there is a place for it so it must be legit), I guess I'm also confused by the use of ambient occlusion into reflection, not critiquing it at all, just intrigued by the thinking process behind it. I'd like to adopt some of this into my own surfaces, but I hope for a little explanation of some of the thinking involved.

Sanchon
03-21-2015, 02:11 AM
I will explained it deeper soon with examples.

jasonwestmas
03-21-2015, 08:35 AM
It appears the logic of this setup is to use specular and diffuse models for most of the blurry shading. Then using fresnel, occusion and a simple normal map to regulate the strength and curvature of the reflection. Using backdrop simplifies the reflection of course to just add in some simple accents where it counts.

Very interesting stylization perhaps.

erikals
03-21-2015, 04:33 PM
looks nice, would you know how does it compare to this one... ?
http://forums.newtek.com/showthread.php?123357-Nodes-and-translucency-again&p=1211421&viewfull=1#post1211421

Shiny_Mike
03-21-2015, 07:02 PM
looks nice, would you know how does it compare to this one... ?
http://forums.newtek.com/showthread.php?123357-Nodes-and-translucency-again&p=1211421&viewfull=1#post1211421

I've tried Pavlov's trick in that thread of using a sky colored dome (Spec only) for fake refl on leaves, fast and works really well. Haven't tried it with DP Sky light, but would probably work nicely, maybe even faster?