Hi all,

This one's a hypothetical, to satisfy my curiosity.

Those of you who use Bryce will be familiar with the memory-saving technique of using semi-transparent 2D Pict objects of trees to populate a forest. Is there an equivalent technique in Carrara ? ...

I ask this as replicating a 3D tree can become memory intensive.

On a related note, I believe that C8 Pro might be introducing ecosystems. Will this be a more memory-efficient way of populating forests ? 

thanks,
Andrew

In Carrara we have the brilliant Replicator and Surface Replicator. (Have had for several versions)

Don't know where you got that idea about C8--don't we have it allready--allways?
Brian

bwtr,
I am aware of the replicator tools. As I said, using these can become memory intensive. I guess my question is more along the lines of -- is it possible to set up the equivalent of the Bryce 2D pict object in Carrara ? 

Re ecosystems, they don't rate a single mention in the Carrara manual, so I guess that means that they don't yet exist.

regards,
Andrew

I think Billboarding is the technigue you are thinking of. 2 billboards intersecting in the middle to give the full tree illusion. Games use this all the time.

I can't see why you could not do it in Carrara.

Yes you can do billboards (called Splats in Carrara)as an alternative--but generally the Surface Replicator would be  better I suggest.  Easy as pie!
,,
.http://tutengraphics.com/tblib.php?lib=Computer Artwork/Carrara 5 Pro Images

Brian

Splats is exactly what I was looking for.
I know how to use the Surface Replicator, but as I said memory becomes an issue the more objects you add. Unless of course you use the splat object within the replicator.

Splats and add the look at modifier - so they are always facing your camera. Splats and the replicator should be just the ticket for speed.

As they said the splat then you could replicate those :) I was reading though can't find the post where some of Howiefarkes have over 1,000,000 trees in them.  http://howiefarkes.cgsociety.org/gallery/559385/  he talks about running into the then version of carrara limit of 10,000 per instance and he had over 100 of them.  I am not sure if that is still the limit or not.

Carrara has instancing which is nice. Thus using duplicates of a given tree model doesn't have the heavy memory footprint like it does in Bryce. But yeah, if you wanted you could still do the splat method. (It's likely it would render a lot faster at least. Less collisions to detect and all that.)

Using the basic Surface Replicator--with all the potential variations--seems the obvious and most logical way to go.
 
Why go down any other track?

Brian

I have to agree with Brian.  I have used literally thousands of trees with the surface replicator with no noticeable slow down in Carrara.  The memory requirements for replicated objects are very small.

Klebnor

Made a few tests last night with surface replicator.

Used non-Carrara plants (objects, some complex), it worked perfectly.  Lots of plants (6000 +) caused some delay while populating the grid, but rendered quickly.

I then tried replicating a building and again, it worked just as expected, without undue overhead.

I find the surface replicator amazing.

One other thing - I haven't played with them, but splats normally follow the camera?  I didn't think you had to use the "look at" modifier.  Some more experimenting is called for.

Klebnor

Here's a quick render using the surface replicator and 3 splats/billboards using the Point At modifier towards the camera with the constraint set to Y+. Several more splats would improve the variation but pretty fast to pull off. (you can click the image to see it larger)

Hmmmmm, I think I need to add the tail of a plane and some traces of smoke coming from the area.  ;-)

wow, very nice ! ... looks pretty realistic to me.

Mark, gotta ask a followup, are you saying there is nothing but splats in that shot?  No real 3d trees?  And you just used mutiple instances of the same splat using the replicator?

Because if so, that's awesome.  I always assumed that if you did a render of a tree and turned it into a splat that the shadows wouldn't look right since it's a 2d image instead of 3d.  But that scene looks great, I didn't see anything which would make me think the shadows looked wrong.

 Just three splats. The scene rendered in about 40 seconds after the grid filled which took about 20 seconds. This doesn't use Global Illumination - I just set up 5 non-shadowing distant lights for the ambient light effect (much better than just using the ambient fill light which flattens everything out)

What you do need to do is duplicated the texture map into the Translucency channel (and dial down the strength) so that the trees interact with light in a believable way. When the trees cast shadows on each other, it naturally diminishes the illuminance of those behind it. 

For the most part, trees are lighter on the outside and shaded more in the middle because of natural ambient occlusion. So, the splat just needs to have that look also. Then the "halo" effect is performed by the Translucency in the shader. 

Wow! Very cool! Thanks for the tips Mark.