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how to render grass properly?

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Re: how to render grass properly?

Unread postby vandam » Mon Apr 15, 2019 10:09 pm

while we're on the subject of CPUs - does Clarisse take advantage of AVX instructions?
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Re: how to render grass properly?

Unread postby sam » Thu Apr 18, 2019 5:58 pm

Not in any major ways. This tends to complexify the writing of shaders if done properly. Then the real benefit is kinda lost in secondary rays unless doing ray sorting which we don't.
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Re: how to render grass properly?

Unread postby Kramon » Fri Apr 19, 2019 5:43 pm

kirkr22 wrote:I have pretty old 3770k. Threadripper would be nice indeed. Together with taxes It's still too expensive although and worth of several super cool video cards.


What? i just checked prices on amazon.
RTX 2080ti founder edition cost 1669 euro on amazon
AMD Ryzen Threadripper 2990WX (32 cores) cost 1845 euro on amazon
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Re: how to render grass properly?

Unread postby kirkr22 » Sat Apr 20, 2019 5:46 pm

well, I see $1,097.50 for RTX and $1,699.99 for 2990WX. It's on amazon where I would have yet to pay taxes extra for importing. I even don't know how much. In our local stores 2990 turns to be exactly twice of RTX And to be honest, RTX is a bit beyond of what I meant. I have GF 980ti now and Octane still renders super fast on it
Also with thread reaper you actually have to buy a whole new system , new RAM , new MB
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Re: how to render grass properly?

Unread postby ionut_armasu » Wed Feb 03, 2021 12:36 pm

Hi there...

I'm puzzled to see that what is a Clarisse issue, is presented as an user hardware limitation.

I do have the same issue and not even at 1024 samples for AA and shading the grass is not looking right at all. Very noisy and barely visible at the tips due to thickness of course. To be more specific,I am referring to adaptive antialiasing. The normal AA works kind of alright despite not being no where close to octane for example. And this is happening only rendering via image view.

And I do have a thread dripper 3990x to put it to work for it.

So, shall we all know how to render grass properly or should I raise a technical ticket for it and wait for the faulty software to be repaired?

Update: I did raised the ticket and the answer is basically that is not a bug.

Thank you!
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Re: how to render grass properly?

Unread postby Akam » Sat Feb 06, 2021 3:10 pm

Hey Ionut,
what you describe as faulty software or bug is just not true. It seems more that you don't know how to setup a proper render in Clarisse.
"And this happening only rendering via image view", you wrote. So this doesn't happen if you use the render manager? Maybe you haven't checked "Always compute full quality image" under preferences/image view since it renders only to 50% if not zoomed in at 100% then.

And to justify that Clarisse is able to render "nice grass" look at the image
renderd on a 1950x threadripper ( actually slower than your setup)
took about 2:30min
64 AAA samples
grass.jpg
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Re: how to render grass properly?

Unread postby ionut_armasu » Sat Feb 06, 2021 4:55 pm

Make the scene to be pitch black, no directional light that there is by default,no hdri, add a spot light on top, make that spot light soft, put the camera to be closer to the ground and at a distance where the grass strands will be visible almost as hair strands and (very important) add SSS to it and you try to get clarity out of that Good luck! :P
This problem is predominantly in very difficult light set-up especially when using adaptive AA with blackman harris filter and with a camera positioned at a distance where the grass strands will appear to be very thin.
And for the render you have, yeah, looks nice and I wouldn't have a problem with that despite I would try to get more out of that.
Last edited by ionut_armasu on Mon Feb 08, 2021 9:47 am, edited 3 times in total.
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Re: how to render grass properly?

Unread postby ionut_armasu » Sun Feb 07, 2021 12:24 pm

Yes, yes, it renders nice grass in most of the cases. However,in extremely low light conditions, having SSS applied, it doesn't and it is noisy and it takes ages to render and the AA is barely decent unless one increase the samples to quite big numbers or increase the resolution. If one can accept for 1 frame to wait hours just for the gras to not be noisy,than is not a bug.
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Re: how to render grass properly?

Unread postby Akam » Mon Feb 08, 2021 11:10 am

SSS on flat surfaces with no thickness makes no sense and also doesn't look good, better go with backlighting in that case, looks better and no noise like with sss. That goes not only with Clarisse but also with other render engines ( especially for pbr render)
In Vue you don't have pbr and if you have sss on your textures and use them in an ecosystem Vue deactivates the sss, so you only get it without ecosystem. And Clarisse has multiple scattering by default which is not always needed and adds of course noise and rendertime, for example it is by default activated for clouds, but most of the time you won't need it and better deactivate it.
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Re: how to render grass properly?

Unread postby ionut_armasu » Mon Feb 08, 2021 5:21 pm

Oh well...I consider that grass done with backface light is a cheap fake that does work mainly for scenes when the grass doesn't count or is not the subject so, you could even leave it without blackface light. And if clarrise can't do SSS in an efficient manner, maybe I should call it Twinmotion instead of clarrise. Besides,if I remember correctly, backface light is not dependent on the lights that are effecting the scene(in the sense that the shadows will not actually influence the result of backface light effect despite you might have the impression that looks right), so this fake thing will work up to some extent if one is willing to give up on realistic results. For me, that grass with backface light is looking more like the artificial turf that I've seen on sale when I wanted to buy in real life, is not nice grass... We can call it fake-paperlike-lifeless type of gras that,by closing one eye when we look at it,we could accept it as being nice just after we wake up in the morning and we can't see straight. Of course,by putting the work in it, one could make look a bit better but still lifeless is.
Now that this subject is done, I can say that Vue can have SSS on a the grass/moss that is populated via ecosystem and is not only for individual plants as I achieved it without issues(see attached picture). Not very big resolution because is a crop but enough to prove the point I suppose.

Anyway... I'm off...I don't invest any more time in this discussion...I rather render some grass instead, preferably life-like type of it, the one that some of us would call it,well..."nice".
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20210208_120555.jpg
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