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#1 2016-08-12 11:10:18

lyonelDahu
New member

displacement for animation

Hi guys !

First post on the forum, so first time to say that Guerilla is really awesome smile. Well done guys, you did really great work here ! It's quite straightforward and very powerfull, I love it !

I have a noob question though, and this is my first project with Guerilla, so sorry about that... I'm trying to render an animation, with some displacement on many objects. I have one tileable map projected through a triplanar node on those geometries. Neither the objects nor the map are animated (just the camera). However, when I render the whole sequence, the displacement make some of those objects (not all) poping up on some frames. Any idea about what's going on ?

Thanks in advance for your help !

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#2 2016-08-12 21:49:16

Narann
Member

Re: displacement for animation

It's difficult to answer without visual. Have you any pictures to share?

Can you reproduce the problem in interactive?

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#3 2016-08-13 00:34:36

lyonelDahu
New member

Re: displacement for animation

No, the problem doesn't show up in interactive mode... I'll post two images when I'll get back from holidays next week smile.

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#4 2016-08-23 07:07:52

lyonelDahu
New member

Re: displacement for animation

So here are two images, to play one after the other smile.

https://s15.postimg.org/ggvbnlq93/rlr_main_Beauty_0001.jpg

https://s15.postimg.org/i9y8bxbfr/rlr_main_Beauty_0002.jpg

Any ideas ?

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#5 2016-08-23 09:31:43

hulud
Guerilla dev, the guy to hug

Re: displacement for animation

Hi Lyonel,

Can you make us a sample with one of those poping objects ? It will be easier to answer.

Pretty cool project by the way wink


Cyril 'Hulud' Corvazier
Guerilla developer
http://www.mercs-eng.com

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#6 2016-08-23 11:16:33

lyonelDahu
New member

Re: displacement for animation

Hi Cyril,

When you say a sample, you mean a scene whith one of the poping object isolated ? If yes, where can I post it then ?

Thanks for help and compliments smile.

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#7 2016-08-23 15:01:14

hulud
Guerilla dev, the guy to hug

Re: displacement for animation

Yes that's it. I send you a PM with my email.


Cyril 'Hulud' Corvazier
Guerilla developer
http://www.mercs-eng.com

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#8 2016-08-24 16:17:03

Narann
Member

Re: displacement for animation

This project looks very cool! Keep the good work.

About the displacement, just a note: We also had similar displacement problems on Ballerina; some displaced objects had "popping" geometries. We were not able to isolate the problem as removing other geometries tends to remove the problem. I suspected a hash trouble in displaced geometries or that displacement sometime use various mipmaping levels, I don't know why (tile hashes?).

The problem were very rare. I guess we had it in two fixed shots or so, so we simply freeze the problematic part in comp.

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#9 2016-08-24 19:01:47

Ben
Guerilla dev, the guy to hug

Re: displacement for animation

Hey guys!

When that happens, please report it because this is a serious issue!

Kind of looks like a displacement shader which is badly evaluated, or faulty derivatives (which cause displacement maps filtering problems.)
Or perhaps caching troubles (displacement is not properly hashed, and instanced geometries are wrongly aliased)

Ben


Benjamin 'Ben' Legros
Guerilla developer
http://www.guerillarender.com

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#10 2016-08-24 20:07:35

Narann
Member

Re: displacement for animation

I wanted but:

We were not able to isolate the problem as removing other geometries tends to remove the problem.

sad

That's why lyonelDahu if you can isolate the problem it would be great! smile

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#11 2016-08-24 21:56:40

Ben
Guerilla dev, the guy to hug

Re: displacement for animation

Yeah I understand.
I had a similar issue once, the cache was missing some info, so it really looks like familiar.

So Lyonel, please PM us with the whole scene (if possible) we'll check what's going on. By the way, which Guerilla version are you running on?

Best,
Ben


Benjamin 'Ben' Legros
Guerilla developer
http://www.guerillarender.com

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#12 2016-08-24 21:58:21

Ben
Guerilla dev, the guy to hug

Re: displacement for animation

And also, thank you Narann for your reports, they're so full of info!


Benjamin 'Ben' Legros
Guerilla developer
http://www.guerillarender.com

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#13 2016-08-25 12:57:58

hulud
Guerilla dev, the guy to hug

Re: displacement for animation

Ok I have an explanation.

The TriPlanar node does worldspace transformations, so the Displacement System must be set "Current" and not "Object".

When the Displacement System is set to "Object", Guerilla thinks the instances (same object with different transforms) are still instances after displacement. Which is not the case if the displacement is doing world space transformations. If the first displaced instance is not the same from a frame to another one, it flicks.

We will correct this and detect that the sub shader is doing world space computations automatically but in the meantime, set the Displacement -> Displacement System attribute to "Current".

Cyril


Cyril 'Hulud' Corvazier
Guerilla developer
http://www.mercs-eng.com

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#14 2016-08-25 14:51:02

lyonelDahu
New member

Re: displacement for animation

Yes, now I think it's working ! That's really great, thank you so much for your help and explanations ! Now it all make sense.
Once the animation is over, I'll post it to show you how it looks smile. It's not really different from the pictures I posted earlier, but with a bit of compositing, it looks a bit better. Cheers !

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#15 2016-08-25 17:48:15

hulud
Guerilla dev, the guy to hug

Re: displacement for animation

Great ! Thanks for reporting the issue, and keep the good work !


Cyril 'Hulud' Corvazier
Guerilla developer
http://www.mercs-eng.com

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