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Author Topic: Best gfx card for heavy forest scenes, or is it more cpu dependent?  (Read 586 times)

Screenscene vfx

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Heya Folks,

I'm doing a very large digital environment shot with a huge amount of trees and details in them. It's my first time using forest for something so big and my viewport update is pretty laggy when attempting to change frames. The scene itself is using lots of objects loaded from forest libraries that are set to xref to allow us to keep small file sizes and tweak materials with easy updating. This makes total sense when as scene is being opened and all the geometry has to be referenced in, but it's also quite nasty in terms of viewport update.

Once forest has calculated all of the distribution points for an object, we're down to it just being a display thing mainly isn't it? I'm on a 3.3ghz xeon with 24 gigs of ram (the scene is taking about 12 to hold in memory) and I'm currently on a geforce gtx 970. There might be a possibility that the motherboard bus is choking the graphics card (it was previously on a quadro 4000) but I'm trying to think of other factors that'd have a major impact on the update of my forest scene. If I have a single forest object isolated, it's still taking upwards of twenty seconds to jump from one frame to another, and it puts a full hit on one of the cores of my CPU.

I'm using large distribution maps (about 6k) and point display mode for each of my 8 forest objects, what do you think would be the biggest contributor to viewport slowdown?

Is there a big overhead aside from the initial calculation of using xreffed assets?

Cheers!

John
« Last Edit: June 23, 2015, 07:01:35 PM by Screenscene vfx »

Michal Karmazín

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Re: Best gfx card for heavy forest scenes, or is it more cpu dependent?
« Reply #1 on: June 24, 2015, 12:59:32 PM »
Hi John,
Quote
"If I have a single forest object isolated, it's still taking upwards of twenty seconds to jump from one frame to another, and it puts a full hit on one of the cores of my CPU."

That's really unusual performance hit, even that sometimes very large areas are quite resource exigent. Are you using animated geometry?

There is option under Display - Build - Manual Update, which would disable updating of Forest object in Viewport (in some specific situations it could be handy) - with this option marked the Forest object will be updated just during rendering process.

Usually, very good performance is given by the Points-Cloud mode, but in some cases Adaptive / Proxy modes would give better results. I would suggest you to switch between those, to check if there is any significant improvement.

Apart of that, let me mention, that when Camera's Limit to visibility feature is used, Forest is forced to rebuild, any time camera is moving. To deactivate it, you should use the Clear button and double check you have the Auto assign to active view unmarked.

Even that all view-port rendering is handled by 3ds Max and Forest Pack has no influence on it, the problem eventually might be related to the graphics driver. Would you please try to change temporary the 3ds Max's display driver from "Nitrous" to "Legacy Direct3D", to check if there is some difference (Customize - Preferences - Viewports - Choose Driver).

Hope you'll find these hints useful.

Best regards,