Help needed restricting a population.

[duff]

I am trying to use a density shader to restrict where grass 'grows' in a scene. I have therefore created a surface shader with an altitude limit as an input to the populatin via it's settings window and ticked the relevant box (note - On the surface shader I have tried using min and max altitudes and making the surface layer black or white) but it appears to have no effect on the grass population. In the same scene I used an identical method to restrict some palmetto tress from going below the same altitude which worked.

Looking at the node network for the population (I opened the node network from teh surface shader and went up a level) I can see that my grass population appears to have a grass clump and a density shader input (see nodes1.png) and this can also be seen in the population settings window (see pop settings.png).

However looking at the object node you can see the grass population appears to only be connected to the grass clump (see nodes2.png). There is not even an attachment for the density shader. Above it is the palmetto tree which has been successfully restricted by a density shader and this can be seen connected to an input on the population.

I have read several of the tutorials and posts and thought I understood how to do this, especially as my trees worked fine, but I assume I have missed something along the way. Any advice would be greatly appreciated.

[Will]

is the grass sitting on the terrain?

Regards,

Will

[duff]

Yes. It sits on the terrain.

[Will]

what else is the palmette conencted to?


regards,

Will

[duff]

The palmetto population is connected to a palmetto object and the surface shader.
The grass population however is only connected to the grass clump object and appears to have no other connections. However I assume nodes1 is actually the same grass population, but here has 2 connections, 1 to the shader and 1 to the grass object.

(note the tgd is the same as the one in my support post http://forums.planetside.co.uk/index.php?topic=842.0)

[Will]

ok I'll check out the .tgd hold on

Regards,

Will

[Will]

do you want your grass on those islands in the distence? becuase your population don't even reach them.

Regards,

Will

[duff]

no the one by the camera - it may be out of view on the right in that tgd. I just want it stopping a couple of feet before the water level.

[Will]

oh alright, I'll work towards that then

Regards,

Will

[Will]

ok I think I got it, you will need to fine-tune it a bit but what you need to do is in the surface sahder in the altidute constrants there is a box that says "use Y as altitude" check that and set your min altitude to around 925 or so.

Regards,

Will

[duff]

cheers, I'll give it a try.

[Mandrake]

http://forums.planetside.co.uk/index.php?topic=730.0

I've asked Big Ben the same question in his above image masking thread.

[Oshyan]

"Use density shader" was not checked (not turned on) in your Grass Clump population. This is of course a fundamental necessity to get density limits to work. However Will is also correct, you will need to check "Use Y for Altitude" to get the altitude constraints to work properly here. In any case I think you will find that with your current settings the grass wouldn't even be visible from your current camera perspective.

- Oshyan

[duff]

yeah - I changed the view and obviously turned off the shader to try a dusk render which ended up as the post in the support forum. I did have it turned on when I was doing the one with grass in -> see pop setting.png in the first post

I don't understand why the grass population node only has one input (and the blazing star) when the palmetto population has two. The missing one appears to be the density shader as the object node is attached.

Still not had any luck but but only had one quick try as was doing something else....

[Oshyan]

The Palmetto is using an existing shader that is outside the object node. Connections to external nodes will show up externally on the node in that way. Connections to internal nodes, as in the case of the grass population, will not show up in this way since they are attached to a node *inside* the grass population. This behavior may change in the future as it is admittedly a bit confusing. But in any case it makes no difference as far as your population density limits - both are connected in the same way, one is just connected to an external node.

- Oshyan