Raytrace Recursion

[supernovavfx]

I have read the 'definition of this'    can anyone add an easier sort of real world explanation of what "benefits" raising this number gives my scene.

 

I have done numerous tests with my complex transparent and reflective logo and cant really see the difference except longer render times... I want to max out 

 

my quality settings for my new promotional material and id like anyones input here.... thank you.

 

Scott

[Thomo]

I know that if you use clip maps with raytrace you have to up the recursion sometimes if they are overlapping planes. Clip map leaves on trees I get a lot of this problem, they just have black artifacts around them unless I step up the recursion.

For clip maps I always set the transparency tab to raytrace and then in transparency settings use irradiance instead of layers. This speeds up clipping a lot.

All that is from the Igors and Tomas. Thanks!

 

Don't know if that really answers your question though.

[supernovavfx]

that is a GREAT answer Thomo... really what I was looking for was some OTHER use of that setting to help elsewhere...  honestly, what I "thought" recursion was... was when using transparency and refraction the number of "bounces" so to speak that camera would use in its analysis... the higher the setting, the more accurate the detail realized in complex reflections and refractions...   I dont know if i worded that very well... but render times increase and Im pretty sure ive seen this work on some glass scenes ive rendered in the past...  I also know that lowering it to say, 5, speeds raytracing along and many times without a visible quality difference...   Ironically im starting to get more into plants and trees so your input is very welcome.  

 

thanks...

[Thomo]

Ok that's good to hear.

With the clip map trees (such as Xfrog) you will see the shapes of the actual polys against a background or rotoscope map. The alpha channel will also be the shape of the polys so it is of no use.

So you need to render another pass just as phong to get the correct alpha channel. Seems like a pain to do but is quite easy. You literally turn off any rotoscope in the camera and change the render window setting to phong. You are only after the alpha channel out of that phong render. Then use that as your alpha mask. Clips the trees perfectly!

So usually with clip map trees I would render one image as full RT and GI, one as phong and one of the background image. I use a lot of HDR sIBL so matching the background to lighting, reflections, etc. is important. Hence the rendering of the correct background. You could put any background in you like of course.

 

Thought that might help as well if you are getting into trees.

 

best regards

[supernovavfx]

99% of what i do is animation... plant factory is what im testing out now... they dont seem to use clip maps.   What im struggling with is exporting and understanding what to look for upon IMPORTING the textures....  Ive rarely had to use UV mapped things in my career but from what I understand thats just ONE map that simply places things properly on your tree if you check the uv box.   But I appear to be getting multiple textures in my export tests.... I emailed some of the tree people but get no response... its hard.. i have 23 yrs experience in animation yet STILL have beginner like questions that seem to get pushed aside with some of this more advanced software...  but im still trying...  the manuals just assume you get how to do this stuff...

 

thanks Thomo

[Thomo]

99% of what I do is still images, however right at this point I'm trying to get an animation rendered with 3D trees. It is new to me with animation.

Plant factory looks good.

I really think we need a share library with EIAS. Making trees I don't want to, but I'll buy 'em or trade 'em! Can you do that? Buy a tool like Plant Factory and sell trees? Or is it still; you buy the tool and everything you make is yours! Only yours. Ala Onyx.

I just can't grasp that concept. buy a tool, not cheap, make something. Can't sell it!!

 

 

Xfrog trees have a selection of particular species throughout the world. They are good to a point, but same thing, support response was; buy it ,if you don't like it I'll give your money back. Maybe they have moved on, fair enough.

I used Xfrog trees for this current project; still images and animation. In hind sight Onyx, which I put aside because it was polygon intense would have been a better solution. Clip map Vs polygon, seems polygon wins! Particularly for render speed and hence animation.

 

Saul

[supernovavfx]

when ONYX no longer supported EI I saved out a chunk of all the tree styles and have them in my source folder for future use in stills or animations.   I have no idea about the selling of trees or trading... i "THINK" you can...  who is to say i did not pay you $1 for 15 trees or plants made by my version

of the software... sounds legal to me.   I am looking into a LOT of options for selling content that can make an animators life much easier and tools to help people achieve certain looks much faster as well....   its a weird market.... some seem to be doing well and others seem to be almost junky freeware

type sites for models and more.  Im researching whats out there and if I may be able to repurpose some of my resources for sale.   PF allows you to make totally original hybrids directly from a source so selling it should be allowed and easy, but it also seems that there are a number of "free"   models out there

that make the effort of doing it yourself interesting.

[thingmaker]

Saul, according to e-on you can create trees for you personal use but to offer them to anyone you must sell them though their other site http://www.cornucopia3d.com (so that they can get a percentage). I bought Plant Factory Studio for $400. when it first came out but haven't put anything on their model site. Prices are pretty reasonable there though. -Derryl

[Arketype]

Hi Scott,

You are essentially correct about raytrace recursions being "bounces".

As i understand it this is how it works.

Each time a ray hits a polygon/ surface that is meant to be reflective, or refractive (trasnparent), it is considered one recursion.

In the case of transparency, each trasnparent surface that you are looking through requires 1 recursion.

The raytrace recursion # is the maximum the raytrace engine will calculate. If this is exceeded, the raytracer stops and returns black as the color. Chances are with 10 recursions, there will be little or no black visible in the final image (there are reflections of reflections of reflections, etc. and eventually... black.)

 

Increasing # of recursions will not increase image quality. With large numbers of overlapping transparent objects, perhaps more recursions would be necessary for propper rendering.

 

If there are no reflections, and no transparency there are essentially no "bounces" in the scene, and the # of recursions setting will have no effect.

 

I am not sure how the photon and iradiance systems work in conjunction with # of recursions, but this would be good to test.

 

One idea might be for you to take an existing scene and start rendering with 1 recursion, then 2, then 3 to see the effect.

 

I used to drop # of recursions to improve rendering speed on some scenes. I could often get as low as 5 recursions, while maintaining good image "quality".

 

If you do any testing please post some images so we can see.

Dave