Zybrand Grass 3

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Zybrand Grass 3Author: Zybrand Lourens
Updated August 2012. Hey everyone, I know there are already a few grass creation compounds out there but I decided to add the one I am working on anyway to get some outside input. I am using this project to expand my ICE knowledge and the grass compound is just a simple grass painting tool for now.

how to use: First create the mesh which will emit the grass and apply two weight maps to it one called »weight map« and one called »Height map« Create empty point cloud and apply ICE tree Connect the Zybrand_Grass compound to the ICE tree and connect the emitter object to Geometry port If the grass compound is still red open the PPG and at the top pick the weight map .weights and then the height maps .weights Additionally to control the color through ICE connect the color attribute to the diffuse of the shader and set it to ColorAlongStrands (in the ICE tree the color along strands gets blended with the color variation of the particles, and that can all be controlled from the grass PPG)


A new walkthrough video turtorial is available here. For version 3 updates, more infos and screenshots see the si-community thread.

local backup: zybrand/Zybrand_Grass_3.rar

jacobo
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Enigmatic Problem with Strand Size

Post by jacobo » 11 Oct 2012, 15:13

Hi;

I have run into a really bad problem with Strand size in v3. It started acting as though the strand size is being projected unto the strands in screen space (????) I've never seen anything happen like this before with strands. I'm on SI 2013, and am wondering if that's the cause :-s I'm including 2 screenshots, one with the camera zoomed in, and one zoomed out.

Zybrand, help... :((

Cheers

AJ
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ace63
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Re: Zybrand Grass 3

Post by ace63 » 11 Oct 2012, 16:26

With mentalray I think the strands can be changed between screenspace and world space by setting the ShapeSizeAbsolute ICE attribute (boolean)
See http://www.chaosgroup.com/forums/vbulle ... _thickness

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Zybrand
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Re: Enigmatic Problem with Strand Size

Post by Zybrand » 11 Oct 2012, 17:41

Thanks for all the positive comments guys :) . Deformations are on the to do list.
jacobo wrote: It started acting as though the strand size is being projected unto the strands in screen space (????) I've never seen anything happen like this before with strands. I'm on SI 2013, and am wondering if that's the cause :-s I'm including 2 screenshots, one with the camera zoomed in, and one zoomed out.
Hi Jacobo, if it is the strands doing that by default it's unintended. I suspect it could be a render issues though because nothing it the ICE tree is linked to distance from camera. I'm not in front of my own pc right now but I'll have a look at it tomorrow. Are you rendering with Mental Ray?

jacobo
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Re: Zybrand Grass 3

Post by jacobo » 11 Oct 2012, 23:51

Hi Zy;

Yes, I'm using MR. The thing is that I went ahead and replaced the V3 ICE compound with its predecessor and the result came out as expected, the thickness of the blades were as specified in the compound ppg in world space instead of screen space. Could 2013 be a problem here?

Cheers;

AJ

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Zybrand
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Re: Zybrand Grass 3

Post by Zybrand » 13 Oct 2012, 09:43

jacobo wrote:Hi Zy;

Yes, I'm using MR. The thing is that I went ahead and replaced the V3 ICE compound with its predecessor and the result came out as expected, the thickness of the blades were as specified in the compound ppg in world space instead of screen space. Could 2013 be a problem here?

Cheers;

AJ
I think your right Jacobo, it is a 2013 thing. I didn't notice the problem because I was using Maxwell to render or just because I didn't test on a large field and wasn't looking for it #-o
Good news is I fixed the problem :D . I had to add a attribute called ShapeSizeAbsolute, that set everything to world space because it seems to be screen space by default. This is the first time I had to add this so I think its new in 2013 because my previous build was done in Soft 2011.

I re-uploaded the compounds on the first page with the fix. I you are already far along in a setup you don't want to redo just add this to the end of you ICE tree:
Capture.PNG
you will need to tweak your thickness somewhat.
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jacobo
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Re: Zybrand Grass 3

Post by jacobo » 13 Oct 2012, 15:33

Dear Zy;

Thanx so much for the fix. I'll give it a whirl right away. Thanx again for this lovely set of compounds, you're definitely a great sport. I'll post a holler here if I come across something, but everything seemed to be working fine other than the size problem.

Take care and god bless;

AJ

valentine
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Re: Zybrand Grass 3

Post by valentine » 23 Nov 2014, 18:07

Quite a while since the last post on this thread... ;) Gonna try anyways:

I got some serious Problems getting this compound to work on 2014 SP2: Create an emitter mesh (Grid), create empty pointcloud, add ICE tree to pointcloud, grab emitter mesh via Get data, add Zybrand grass, connect emitter mesh to Emitter input of grass, connect grass compound to Port1. Grass node stays in red state and the error message says:

[...]
WARNING: This branch cannot be evaluated.
ERROR: Attribute StrandPosition is not initialized on object pointcloud.pointcloud
ERROR: Attribute Orientation is not initialized on object pointcloud.pointcloud
ERROR: Attribute EmitLocation is not initialized on object pointcloud.pointcloud
[...]

Since I haven't been much into ICE, yet, my efforts of fixing this problem weren't successful. Even Google has never heard of one of those Error messages, so I'm pretty lost. Any help getting this very promising compound to work would be really appreciated.

Best regards,
valentine

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rray
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Re: Zybrand Grass 3

Post by rray » 23 Nov 2014, 20:23

The emitter mesh needs a weightmap to contol the grass density. These are all follow-up errors, it would be nice if ICE would trace them back to the thing that caused them.
softimage resources section updated Feb 7 2019

valentine
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Re: Zybrand Grass 3

Post by valentine » 24 Nov 2014, 22:33

rray wrote:The emitter mesh needs a weightmap to contol the grass density. These are all follow-up errors, it would be nice if ICE would trace them back to the thing that caused them.
Hi Reinhard,

Thanks for your quick reply! Unfortunately I already tried to fix the problem by adding weightmaps without luck yesterday (see Attachment). Any other ideas?

Best regards,
valentine
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FXDude
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Re: Zybrand Grass 3

Post by FXDude » 24 Nov 2014, 23:41

In his video he names his height map weight map to "Height_Map", I don't think it should matter or change anything, but perhaps would it be name specific?

theboykidney
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Re: Zybrand Grass 3

Post by theboykidney » 29 Jul 2015, 13:29

Late to the party on this one, but is it possible to have flat strands of grass instead of cylindrical ones?

NNois
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Re: Zybrand Grass 3

Post by NNois » 29 Jul 2015, 21:46

theboykidney wrote:Late to the party on this one, but is it possible to have flat strands of grass instead of cylindrical ones?
this is up to you renderer ;-)
MR: you can change the particleshape to rectangle http://softimage.wiki.softimage.com/xsidocs/ICE_particles_ICEParticleBlobs.htm
Arnold: you can change to Oriented Ribbon https://support.solidangle.com/display/SItoAUG/Strands
so it depends...