Preferred grass objects

Started by rossy96, August 28, 2019, 08:48:33 am

Previous topic - Next topic

rossy96

Hey guys. I'm trying to make a scene and I've been messing with the population settings but am never satisfied with how it looks because the populations are almost perfectly circular (in 1m or so diameter) so it looks completely artificial no matter how I do it. I was using wider objects to save a little time but I think using a larger number of smaller populations is unavoidable. I'm using Mr. Lamppost's grass packs as of now and although they work for really lush instances, it's not the look I'm going for. I'm looking for some options for a rocky, populated area which should include a very short grass/moss. Do you all have anything you would use for an instance like this? Thanks in advance.

Dune

Welcome to this forum, first of all. It depends on the view you want. If it's for distance, I'd use procedural (fake) grass (search for fake grass or procedural grass), with population(s) of the internal grass a bit closer by. For really close-up I'd add better grass objects, but you need to populate a few types and have them overlap for a varied grass layer.
For very short, more distant grass, a fake stone based procedural grass will do nicely most of the time. Also depends on how big you need to render of course.

I hope this gives you some idea.

Oshyan

Quote from: rossy96 on August 28, 2019, 08:48:33 amthe populations are almost perfectly circular (in 1m or so diameter) so it looks completely artificial no matter how I do it
Can you clarify this? Do you mean that you are intentionally trying to make realistic, small-scale, circular areas with populations, or that are always getting these small circles *unintentionally* no matter what you do? If you can show an image example that would be even better. :)


- Oshyan

Dune

I think he means the object, not the population. And they are indeed mostly a circle of blades, but the idea is to have them overlap.

Oshyan

Ah, so the *instances* themselves are perfectly circular? Then yes you'd need to just use a different object. Or make the population so dense (lower spacing) that they overlap a lot and hide the regularity.

- Oshyan

cyphyr

Personally I find the "Grass clump" too short and too wide and yes this leads to exactly the problem you describe. The circular edges overlap the area you need filled.  Fortunately this is easily fixed as you can edit the internal Grass clump node.
Dropping the number of blades down to 1000 (from 10000), the diameter down to 1m (from 10m) and the raising the blade length to 0.3m (from 0.1m) gives (IMO) a much more useful and controllable grass population.
Hope this helps :)
www.richardfraser.co.uk
https://www.facebook.com/RichardFraserVFX/
/|\

Ryzen 9 3900X @3.79Ghz, 64Gb (TG4 benchmark 6:20)
i7 5930K @3.5Ghz, 32Gb (TG4 benchmark 13.44)

N-drju

As always - it depends.

I use lots of grass in my renders and yes - most of it comes from Lamppost's excellent pack.

The key (as always?) would be diversity. Many types of grass planted IAW the "three levels" principle - small, medium, large and likewise coverage patterns.

The "Grass clump" object is also very useful, but you need to make quite a lot of tweaks to get it right sometimes.

In renders that are shot from a considerable distance, small fractal displacements mimicking grass are preferable.

And welcome to the forums Rossy. :)
"This year - a factory of semiconductors. Next year - a factory of whole conductors!"

bobbystahr

Quote from: Dune on August 28, 2019, 09:14:46 amWelcome to this forum, first of all. It depends on the view you want. If it's for distance, I'd use procedural (fake) grass (search for fake grass or procedural grass), with population(s) of the internal grass a bit closer by. For really close-up I'd add better grass objects, but you need to populate a few types and have them overlap for a varied grass layer.
For very short, more distant grass, a fake stone based procedural grass will do nicely most of the time. Also depends on how big you need to render of course.

I hope this gives you some idea.
I use mainly your free grasses that were available from NWDA till it closed down...I haven't checked the shared forum here so dunno if you've shared them here.
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist

Dune

No, I haven't had time to see what can be shared here (or elsewhere), yet.

digitalguru

Quote from: rossy96 on August 28, 2019, 08:48:33 amI think using a larger number of smaller populations is unavoidable.
Yes, that's the trick I think, and you need lots of variations - most grass clumps come in circular patches and they are perfectly fine for lush grass as Cyphr demonstrates.  But for the look you're trying to achieve (rough grass growing in between rocks?) it's more 3 or 4 blade variations to get the randomness required. And for that you will end up with  lot of populations - even 3 or 4 variations tend to look repetitive - especially up close. It helps if you have a 3d app (Blender?) so you can prune down some existing grass models and do some basic editing to get a bunch of variations.

I've even tried rendering grass via hair/fur in Maya with medium sucess :)

It is possible in Terragen, but as said, needs a lot of variations for realism, and managing a large amount of populations can get quite unwieldy. I used MASH in Maya to make some grass populations which has an ecosystem mode. You can feed an array of plant models into one node and have them populate a scene and weight selected models over others - it would be great to have that sort of functionality in Terragen.

I've found setting the spacing variation quite high (over 100) helps make the pops less uniform and using a lot of masks helps. For instance, if you have some rain channels eroded in your terrain -  masking that out so grass doesn't grow on it, but on the side of it really helps get a realistic result.