Topic: Grass banking on slopes

[FabioHFernandes]

Good morning...

I´ve been playing with the grass, and i´ve noticed that the grass stands horizontaly in the slopes and i could not bank them to the right inclination..is there something i am doing wrong?

Thanks a lot

Fábio

[Aaron]

Youre not doing anything wrong Fabio.
It's just that Speedtree, the most awesome foliage package in human existence,
doesn't allow it due to it's procedural algorithms.
Who needs sloped stuff anyways right? It's not like foliage, trees and grass
grow on sloped surfaces in the real world......

[FabioHFernandes]

To ilustrate better...



Thanks again

Fábio

[peterm]

Ha, further evidence that the world is truly flat  

Correct me if I'm wrong, but having a look at SpeedTree info it seems that the issue is really how the plant object is made available for use in Lumion.  The SpeedTree plants can be  angled to fit specifically to sloping terrain (not sure though about grasses), but that's only at the create(and compile) stage.  

So Lumion provides a finalised plant, that for simplicity has no pitch or bank in order to fit the majority of scene requirements.  In order for users to have plants sloped, it would need specific plants made with some slope(maybe pitch only) value options such as 10 degrees, 20 degrees as additional plants for the library.  These could then 'fit' most slope scenes but not all situations.  

Further, it would generally apply only to types where the base size of the plant is wide such as some of the grass block types where you notice it not conforming to the slope.  Trees and single grass and plants can generally be positioned to look OK on any slope, apart from ones specifically requiring change in growth angles (topic covered elsewhere earlier in year).

Most of the scene samples from the SpeedTree site are reasonably flat, even the golf game, but there are a few pics that indicate sloping plants for grasses eg here.

If the scene required it and closeup camera work revealed the grasses, then I guess it could be worked around by just using single, non-area sized grasses, so long as the number of objects didn't affect framerates/rendering speed too much.

[Aaron]

That's correct Peter,

Theoretically one could create sloped versions of just about anything that'd require
some form of sloped, angular, pitched or yawned growth.
This way you could even create trees growing upside down and probably, if some effort
was put into it, elephants with animated trunks hanging of their branches.
So, practicalities like browsing through a whopping object library to find the entry you need
left aside, it is possible indeed.
I've done some recent experimenting with precisely the above and it's kind of a annoying process to have to adjust, rotate etc. every single tree or grass-patch until it lines
up on your geometry the way you fancy.
As far as the grass is concerned I'm pretty sure the examples on the IDV site utilize grass implemented via the 'speedgrass' solution. Not saying this enables one to go totally wild
on sloped stuff but it's a somewhat different implementation allowing for a bit of contour/terrain matching.

Perhaps, for now, it's best to just offer some grass as static meshes via the object library.
Edit: I'll do some performance tests on that asap.

[Aaron]

Performance seems to be ok. Just as long as you don't expect this method to give you similar
amounts of instances in the viewport as via Speedtree grass (probably best to put it in a seperate layer anyways).