Forests in maya mental ray.

#441

You did see Duncan’s Tutorial on the area. Its basically a work around, but gives you control to animate sky facing leaves with the sun as well. He also includes sample files. Let me know if you cant find it.
Rasa

#442

You did see Duncan’s Tutorial on the area. Its basically a work around, but gives you control to animate sky facing leaves with the sun as well. He also includes sample files. Let me know if you cant find it.
Rasa

Thanks for the tip! But I have seen his post. I actually mentioned in that same post you quoted that I am aware of that trick. :slight_smile: Only problem is some of the leaves turn upside down and some are right side up. If you are using a two-sided shader that trick does not work. Thanks though!

-Justin

#443

I did see a script that selected similar facing faces.You could apply normal direction and then your material with that right? Or am I totally wrong? I would like to know as well, as I have a tree in the making. I could find it if you thought it was worth a try. I thought of leaves when I saw that script.

#444

That sounds pretty cool! Not sure if it would work or not but I’m willing to give it a shot if you happen to run across it. Would be very cool to get paint fx leaves to be oriented correctly.

#445

I think the Select with constraints tool has a orientation option… you could read in script editor what it does…

#446

Selects faces based on normal direction:
http://toi.bk.tudelft.nl/?module=meldb&page=details&sID=52
Would be cool to combine it with this:
http://wiki.bk.tudelft.nl/toi-pedia/MEL_Sun_Simulator

#447

Wow…that’s a coincidence! I JUST downloaded that toolset, but only for the gamma correction stuff. I didn’t even look at the other tools. I’ll have to experiment with that. Pretty cool!

#448

@syna @mehran

I thought you guys were discussing the issues with flickering grass at the horizon area? Did you guys find a solution to it? I am still facing those issues? I’ve tried solving it by upping my FG point density and then caching the FG map thinking that would solve it but sadly, it did not.

I also went to the Vue website and looked around a bit since they handle so much grass and all.

This is what it says there
"Flicker-Free Plant Rendering Technology
One of the most challenging aspects of rendering natural scenery is the notorious flickering associated with distant vegetation.

Vue’s ability to create scenery containing millions of plants means that for every pixel of every frame, the render engine must handle a large number of overlapping polygons, requiring high anti-aliasing settings in order to get rid of animation flickering.

SolidGrowth 4 technology lets you render even the most densely populated, animated scenes with a minimum amount of flickering using techniques such as texture filtering and proprietary anti-flickering algorithms."

What is the best way to fix this in Mental Ray and reduce all this flickerness? and how much caching is required before its no longer FG’s fault and its that of whatever else is causing the horizon flickering?

#449

some LOD system perhaps. I think I read somewhere they used PaintFX for plants in Avatar and had a custom LOD system that reduced the polys for plants and trees in the distance. Of course Maya’s LOD system may not be so advanced as the Weta/ILM solution (can’t remember which one the article was about) but you could just end up using cards for distance foliage. Same idea really.

#450

The LOD system used on Avatar focussed on reducing internal geometry that wasn’t considered part of the silhouette. By retaining the shape/outline of the trees, at a distance they still conveyed the form of high resolution trees, but with significantly lower overhead.

Most of the hero trees actually had significantly less leaves than a real life tree does. All it had to do was look good in the majority of the lighting scenarios encountered throughout the shots. There were a few instances where shots called for strong backlight coming through the canopy of a tree and the “sparsity” of the leaves became noticable. In which case more leaves would be added.

Paint Effects was largely used to set dress the larger hand built trees. Dressing them with grasses, toadstools, small flowers, etc. God bless Paint Effects! :slight_smile:

#451

i’m made this request on wishlist on the area some days ago

[i]“Dynamically polycount control for Paint effects converted to poly for not increase the viewport”

[/i]I think that it’s on maya 2011 or fututre release, some script writer able to get a LOD script at distance.Quote for God bless Paint effects

#452

That would be an awesome feature. Great idea…and I really hope they implement that!

#453

I’d welcome any additions and improvements to Paint Effects. It’s by far my favorite part of Maya.

#454

kinematics:
Yeah < but I am still drowned in work, so I can’t do tests to figure it out. > however I do think that some sorts of post effects can be used to reduce the flickering. u know like a despeckle system mapped with a depth map, so that it only works on the hotizon geometry, just a thought.
what do you guys think?

#455

Re Flickering…

One of the tricks for Vue is longer renders… more anti-alising. Do a test with min max sample levels at say 2 and 4 or higher and set multi pixel filtering to Mitchell. I would suggest increasing point interpolation and point accuracy, even higher. Your one frame should take 1-24 hours to render. Then you haveVue flicker free technique down lol. You could also try rendering larger images :frowning: and then scaling them all in half later. You could try scaling what you have already as a test.
I am guessing its the edge of your grass, its to thin at those distances.

I would also like to see Poly paint LOD options. It sounds like Duncan is working on some new tree/growth settings, such as the ability to make sky facing leaves easier. Fingers crossed.

R.

#456

I haven’t tried it myself in animation, but have you guys played around with the AA-contrast? Coz it sounds to me that the problem could (I don’t say that it is) be linked
to a too-high of a contrast threshold? Give it a try and take it down to around .025, or maybe even 0.

#457

@ Kinematics

I still couldn’t find the answer for the flickering. I had no time to do more tests because i have lots of work by these days.
I think with more antialising would work but it would be too slow to even consider it a solution.
At the same time i don’t think that mitchel would help as well.
I realy don’t know how vue works but when i have some spare time i will make more tests and post the results.

#458

One of the tricks for Vue is longer renders… more anti-alising. Do a test with min max sample levels at say 2 and 4 or higher and set multi pixel filtering to Mitchell. I would suggest increasing point interpolation and point accuracy, even higher. Your one frame should take 1-24 hours to render. Then you haveVue flicker free technique down lol. You could also try rendering larger images :frowning: and then scaling them all in half later. You could try scaling what you have already as a test.

Indeed, and this is (among other reasons!) the main reason this thread has been so helpful for me. I haven’t touched Vue for almost a year now, and never will again. Absurd rendertimes, instability, and horribly CG-looking trees/plants aside, all I see from Vue nowadays are even grainier, longer renders which are nauseating after seeing what all you wonderful people are doing with Maya these days. And at reasonable rendertimes, too!

I haven’t done much animation really, so I can’t comment on the flicker issue. But Visua’s suggestion sounds as good as any! Think I’ll give it a shot if I get some downtime this week…

#459

that flickering issue is such a pain… I am thinking post effect and doubling my res. sizes… also the contrast threshold comment makes sense, but that would definitely shoot the render time all the way up. like I said 10 mins on an HD frame is cool (not that cool but workable) anything above that I can’t afford , in my working environment (small render farm)…

#460

Actually it happened to me that Mitchell filter enhanced aliasing in animation. It were a bunch of high-frequency procedural textures, not grass. But somehow that case could be similar, since you are thinking that Contrast Threshold could help: grass is geometry, so sampling should be a solution, not Threshold. But in fact, if you consider grass like a whole object, I guess that Threshold, that is referred to color variation, could be the way to go.