[wacampbell]

I've continued with experimenting on terrain texturing methods. Here's an in game shot on my test route. I'm looking at a density of about 5 billboard flats per square meter here.


The visual effect hangs in their pretty well even at direct down angles.


PS Ignore the buildings - they are just placeholders, but some of Paul Charland's excellent CN boxcars provide a good color reference in the scene.

[wacampbell]

Walter Conklin, on 27 January 2012 - 02:24 PM, said:

Would the vegetation shown in the screenshots fall under the category of procedural vegetation?

Yes, although for this experiment the geometry was baked.

[dantheman]

Son of a motherless goat! That is amazing!

[captain_bazza]

Truely amazing! :drool3:

Cheers Bazza

[timmuir]

Wow, that looks amazing. Question, what is meant by procedural vegetation?

[wacampbell]

timmuir, on 27 January 2012 - 05:49 PM, said:

Wow, that looks amazing. Question, what is meant by procedural vegetation?

In MSTS, most of the trees and grass etc are actually modelled in a 3D cad program ( ie TSM) by an artist and placed in the world editor.

For procedural vegetation, the artist just generally says ' I want this part to be grassy, with some taller bushes ' and the CPU or GPU generates all the necessary polygons at the right height to follow the terrain. Normally the term refers to the processor generating these polygons only when needed in the immediate vicinity of the camera. That way computer resources aren't wasted to hold geometry that is out of sight. When I said for my experiment that I baked the geometry, it meant that the geometry wasn't created this way in real time. Instead I used a similar algorithm to generate the geometry but it did so only once when the scene was loaded, rather than creating it just as the area comes into view.

[timmuir]

I get it. I see this in some video games, where as you enter an area, grass and other details appear, but disappear as you move away. I've always admired that and wished MSTS had a similar feature. In Brothers In Arms, some of the grass actually grows out of the ground as you approach it, which is a bit awkward looking. Thanks for the explanation and clarification of "baking" the geometry, which I meant to ask about too but forgot.

[wacampbell]

I've added a little more color variation to improve the appearance. And added a gradual fade till its gone at about 300 meters. The fade is quite imperceptable as you pull back. This leaves about 200K to 300K poly's in a scene like this. This should be manageable by most hardware, but obviously will need to be optioned off for the low end users.

Some of things I've learned from these experiments:

- artist control of terrain color is important ( as we do now through terrtex's but using a more convenient mechanism )
- multiple 'microtex's - you need a different one for grass, vs ballast, vs dirt etc.
- about 5 bilboard panels per square meter works OK
- billboard panel color must be tinted by terrain color to prevent a flat appearance
- a mix of about 4 - 7 weed/grass shapes is good
- don't use cruciform shaped panels for grass ( intersection with ground is too obvious ) - flat panels randomly oriented is better
- clump the weed/grass shapes - random dispersion looks unnatural

Now - how to get all this into OR while providing the artists the control they need ....

[wacampbell]

I'll waste some bandwidth and post a few more shots at full resolution ...

[Genma Saotome]

What does it look like from high angles?

Have you reviewed the Speedtree brand grasses and weeds as built by Bethesda Game Studio (The Elder Scrolls series of games)? Using a change in font to emphasis the shape, they're often done in a W shape with each vertical having two or three kinks in it to produce the spread from the root and are plants done in pairs so the two central verticals overlap. An example from Skyrim:



I would think if our forest software could be enhanced to allow (1)planting of non-billboard shapes as well as billboards and (2) "paint" a set of vertexes instead of dragging out a rectangle, that overlapping zones of weeds could be very effective, just as you show in your work.