Itoo Software Forum

Forest Pack => Forest Pro (*) => Topic started by: Macker on September 29, 2015, 03:08:15 PM

Title: Edge mode & efficiency...
Post by: Macker on September 29, 2015, 03:08:15 PM
Hey guys,

Love using the new edge mode, but I was just wondering this:

If I have a massive site and wish to cover it all in grass (or whatever else you care to think of), because the new edge mode removes any geometry outside of the boundary should I just use a really large patch of grass (say 3m diameter, for example) or is this inefficient because Forest Pro will need to calculate more items to remove at the edges? Presumably there is a tradeoff between the size of the patch you're scattering and the amount you want to scatter? What would you advise as the happy medium?

Basically the project I have in mind is an aerial flyover that then comes down to ground level (which requires the detail).
Title: Re: Edge mode & efficiency...
Post by: Michal KarmazĂ­n on September 29, 2015, 03:54:07 PM

First let me mention, that there is no "physical cut" performed while using the Edge Boundary Checking mode (as this would be extremely resource demanding). The "trimmed part" is treated by the V-Ray render engine as a kind of "Matte object" internally (this way render engine ignores it for its calculations).

But, take in mind, that a "really large patch of grass" might contain a lot of polygons (which wouldn't be ideal neither). I would suggest you to do some testing with diameter about 1 meter, which should lead to about 1M - 2M objects and prepare few variations to get nice look (most of our bundled presets are using clumps size around 30cm). There is no general rule about the size, as that mainly depends on how complex models are used, but distributing very high poly-count items might be quite memory consuming.

Also please note, that for large scenes the recently introduced Forest LOD ( feature is highly recommended (the most common use for this feature is to create Level of Detail models so that less complex models and materials can be used further from the camera to help speed up renders).

Hope that helps.

Best regards,
Title: Re: Edge mode & efficiency...
Post by: Macker on September 30, 2015, 09:33:16 AM
Thanks for the quick reply. Yeah I had considered the forest LOD, but I would have to create some lower poly versions of the grass, etc - which I'm not sure about.