Forum

#1 2014-11-27 22:20:22

paul.parneix
Member

Ocean Project : Particules rendering wip

hey guys  smile,

Working on some flip sim in houdini, wanted to test in guerrilla

Guerrilla definitely CAN deal with a lot particles big_smile Here's a test with 3M max particles (working on the upres on houdini to get 30 M !) pretty fast render !
test with volume shader, rendered as points :
http://img15.hostingpics.net/pics/888166guefoam1.jpg

same with surface shader :

http://img15.hostingpics.net/pics/790271guerillafoam2.jpg

(don't know where the white specular artefact come from ? maybe be i need to clamp something ? )

Will try to do the upres thing in houdini and render a sequence.

Edit : Does someone know the way to do a layered shader in houdini ? like coatinng, or just superposing 2 shaders with a mask ? thanks.

Last edited by paul.parneix (2014-11-27 22:28:54)


FX TD / Artist - 3D and Surface Scan Speciaist.

Offline

 

#2 2014-11-28 02:39:01

Ben
Guerilla dev, the guy to hug

Re: Ocean Project : Particules rendering wip

Hi Paul,

If you're rendering as points, the Surface shader is probably doing something weird (I don't think the point normal is really relevant...)
That may explain the weird speculars...
The Particle shader is probably more suited at rendering points.

Cheers,
Ben


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

Offline

 

#3 2014-11-29 16:24:25

paul.parneix
Member

Re: Ocean Project : Particules rendering wip

Hi ben, thx for quick feedback !

Yeah, it's pretty logic, haven't realized that normals are used to compute spec. but it's kinda strange because the spec pass looks fine on most of the render !

here's a quick render of the ocean mesh (without foam);

http://img15.hostingpics.net/pics/893882guerillamesh1.jpg

Only playing with surface shader settings, trying to import color and velocity attributes from houdini (but exporting attr from houdini to other software is such a pain...)

Is there a way to render motion blur on a changing topology alembic mesh ?

Thanks for your help,

Paul


FX TD / Artist - 3D and Surface Scan Speciaist.

Offline

 

#4 2014-11-29 16:48:39

Ben
Guerilla dev, the guy to hug

Re: Ocean Project : Particules rendering wip

Alembic has a velocity channel which Guerilla understands, for topology changing meshes.
So, that should work fine.

Ben


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

Offline

 

#5 2014-11-29 17:12:20

paul.parneix
Member

Re: Ocean Project : Particules rendering wip

thx for reply, so it should work fine

Houdini abc export gives me headaches XD can't get my color sets or vel in maya.

Will try to export my abc the right way, and post an updated render.

Thanks a lot.

Paul.

Edit : starting the shark shader :p (model by carlos parmentier)

http://img15.hostingpics.net/pics/318930sharkk.jpg

Last edited by paul.parneix (2014-11-29 19:00:04)


FX TD / Artist - 3D and Surface Scan Speciaist.

Offline

 

#6 2014-11-29 23:50:47

Ben
Guerilla dev, the guy to hug

Re: Ocean Project : Particules rendering wip

Yeah, unfortunately Maya doesn't have a velocity channel in its meshes, so importing Abc will most likely loose them.
Are you using Alembic directly in Guerilla or are you going through the Maya to Guerilla export?


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

Offline

 

#7 2014-11-30 00:18:29

paul.parneix
Member

Re: Ocean Project : Particules rendering wip

I'm importing ogawa abc from houdini export. actually I tried using maya and exporter but maya seems to mess with my channels.

the problem is that houdini stores all channels using is own way and nomenclature, and I can't use them in any other software /renderer.

eg : color sets are stored, but not the same way as maya do, so it's not possible to read them in maya (there is a hack using SoUP, and arrayToPointColor node to retarget houdini channels to maya color sets, but it's painfull...).

The Velocity is stored, but same thing, maya can't read it.

Guys from Digic had same problem with arnold and velocity, their workaround is  to store velcoity as a 3float color set and they have a custom script to tell the renderer to use this info as point velocity.

I will upload an abc from houdini in case you're interessed to have a look smile

thanks.

Paul

Edit : for the foam, if I have normals on my points, would it be possible to have an artefact free specular ?

Last edited by paul.parneix (2014-11-30 01:01:20)


FX TD / Artist - 3D and Surface Scan Speciaist.

Offline

 

#8 2014-11-30 01:35:48

Ben
Guerilla dev, the guy to hug

Re: Ocean Project : Particules rendering wip

Yes, if you have this abc, I'll try something.
If you have a coherent surface normal, the spec will be ok


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

Offline

 

#9 2014-11-30 17:20:54

paul.parneix
Member

Re: Ocean Project : Particules rendering wip

Updated render : Ocean mesh + decent Hdri + 40M upres particles

Volume points render
http://img15.hostingpics.net/pics/732345gueocean1.jpg

surface point render :
http://img15.hostingpics.net/pics/582138gueocean2.jpg

(need to fix the delay between ocean and foam)

I'm uploading a low res mesh abc mesh from houdini.

Thx

PS : noob question ; but what is the way if I want an object to be visible in reflection / refraction, but not visible  direclty to camera ?

Last edited by paul.parneix (2014-11-30 17:23:33)


FX TD / Artist - 3D and Surface Scan Speciaist.

Offline

 

#10 2014-11-30 17:44:18

paul.parneix
Member

Re: Ocean Project : Particules rendering wip

Here's a link to download the ABC file (low res fluid splash) : https://www.sendspace.com/file/ahhf2x

I've keep houdini default channels, and added a color channel (Cd by default) which is the magnitude of velocity

http://img15.hostingpics.net/pics/193305houdinilowres.jpg
Thx

Edit : the abc was exported as polygon soup without motionblur checked (but velocity channel is here) here's a version as polygon with motion blur checked :
https://www.sendspace.com/file/i2g7b3

Last edited by paul.parneix (2014-11-30 17:50:10)


FX TD / Artist - 3D and Surface Scan Speciaist.

Offline

 

#11 2014-11-30 21:04:27

Ben
Guerilla dev, the guy to hug

Re: Ocean Project : Particules rendering wip

paul.parneix :

What is the way if I want an object to be visible in reflection / refraction, but not visible  direclty to camera ?

You can either:

- remove the primary visibility of the object, in the Attributes > Primitive > Primary Visibility (the easy shortcut)
- remove the linking to the Layer (the more general way, especially if you want layering)


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

Offline

 

Board footer

Powered by PunBB
© Copyright 2002–2008 PunBB