Another way of making grass

[blowback]

I created an object. mapped a 2d grass map onto that object and distributed it with the particle system in max. Rendered in Vray. There are some minor issues but I am pleased overall with the results.

[Crazy Homeless Guy]

That did work well. What kind of render times did you wind up with?

[blowback]

Ugly ..... a 3000 pix wide image took 27 hrs. There is a building and some 3d proxy trees around as well, + 6 render elements. Something that should have taken an hour or 2. I am just starting to experiment with particle distribution, so I am going to do some test later to see were I cut time, and also blend with maps and vray displace.

[Chad Warner]

By the sound of things, you're basically doing the same thing that forest pack does. The problem with Vray and forest is that Vray doesn't like lots of opacity mapped objects, so in some situations you're better off just using actual geometry.

 

Your result does look very good though.

[blowback]

Ya, I pobably won't use op maped object 4 the entire lawn again ....lol. but it is possible. @ least not with vray

[Sawyer]

Thinking that this may be a great test. What if we set up a scene share it and we all test as many different grass systems and post the results? Any interest in that?

[blowback]

Yep. I would be

[Claudio Branch]

By the sound of things, you're basically doing the same thing that forest pack does. The problem with Vray and forest is that Vray doesn't like lots of opacity mapped objects

 

Forest Pro 3 now handles V-Ray proxies...

[Claudio Branch]

I have used Particle Systems alot. Your solution came out nicely. Perhaps turning off GI for "grass" would help the rendering times?

[blowback]

I have used Particle Systems alot. Your solution came out nicely. Perhaps turning off GI for "grass" would help the rendering times?

 

 

Do I just select my particle object and uncheck receive GI in vray properties?

[Claudio Branch]

I believe that is correct and while your at it uncheck GI for the Particle System itself.

[blowback]

thx Claudio,

 

I will do some tests.

[Claudio Branch]

You might also consider playing around with the Advanced Painter script.(you should be able to seach for it). It is very useful because you can strategically "paint" geometry onto any surface you need it on.

 

I have used Particle Systems, Displacement, Scatter, Forest Pro, Advanced Painter all in the pursuit of geometric grass.

[blowback]

I read about that the other day and I will look into it. I know nothing about painter script but will try it out.

 

I am always on the hunt for better (grass) techniques.

[Tommy L]

Do I just select my particle object and uncheck receive GI in vray properties?

 

No, untick 'generate GI'. This way the grass will receive secondary lighting (wont have a 'dark side' but wont redistribute the GI.

I would also recommend you do this with all displaced elements by the way.

[blowback]

No, untick 'generate GI'. This way the grass will receive secondary lighting (wont have a 'dark side' but wont redistribute the GI.

I would also recommend you do this with all displaced elements by the way.

 

 

thx 4 the tip.

[Nic H]

you have blur at 0 in the opacity map as well?

looks like a good technique

[blowback]

you have blur at 0 in the opacity map as well?

 

 

no ..... I have to check but I think I set it to .5 or default 1 ...... I cant't remember. The file is @ home.

[Nic H]

chuck it on zero, it will speed it up

[Claudio Branch]

Here is a shot created using Advanced Painter and rendered with V-Ray.

 

The grass consists of 3752 grass "plug" proxies.

 

I started by using Advanced Painters' Grass tool to paint a small "plug" of grass. I collapsed the plug down to an Editable Poly, assigned it a material, and then converted it to a proxy.

 

Using Advanced Painters' Scatter tool, I was able to "paint" instances of my grass plug onto a selected surface. The Scatter tool allows me to vary the scale and orientation of each new instance it creates. Setting the display to box or point also keeps my video card from locking up.

[blowback]

ya that looks good! how big is the plug? How many strands of grass / plug? What was the render time?

[Claudio Branch]

how big is the plug? How many strands of grass / plug? What was the render time?

 

The individual plug is shown in the bottom image next to a low-poly car for scale.

 

Each plug has about 250 individual strands.

 

This image took 56 minutes to render on a 64x dual core machine with 2GB RAM.

[Chad Warner]

I don't remember or not with the advanced painter, but can you tell it the number of sides on the strands of grass? It seems like the "cylindrical" shape of the strands will kill you, which 56 minutes would attest to. (depending on what resolution you rendered)

[Claudio Branch]

I don't remember or not with the advanced painter, but can you tell it the number of sides on the strands of grass? It seems like the "cylindrical" shape of the strands will kill you, which 56 minutes would attest to. (depending on what resolution you rendered)

 

You can control all aspects of the individual strand within the AP Grass Parameters rollout.

 

I made my grass fairly robust as well. More testing is warranted...

[blowback]

well,

 

With changing some GI & blur settings I dropped 7hrs. Bringing the render time to approximately 20 hrs. better but not there yet.