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Author Topic: "Transforming vertices" with grass slow  (Read 972 times)

SR1351

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"Transforming vertices" with grass slow
« on: March 12, 2016, 05:55:37 PM »
Hi I am using Forest Pro Beta 5, it is fantastic. But I do have one major issue.  When I hit render on Vray 3.3 "Transforming vertices" takes really long, I know it is do to the grass in my scene. I have a huge golf course and I am scattering one of the preset grasses (Large) for a distance of 600' sometimes 900'. If I turn it of "Transforming vertices" is instant. I have a lot of scattered trees and bushes also, but the grass is what takes forever.  This is happening on two separate projects.  Is there a cache button or something so it doesn't have to calculate every time for so long?

GL3654

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Re: "Transforming vertices" with grass slow
« Reply #1 on: March 12, 2016, 06:53:36 PM »
did you try the LOD (level of detail) or the Distance Falloff feature ?
you can find them in the camera rollout...
you should be able to reduce polycount massively without having a strong visual impact.

SR1351

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Re: "Transforming vertices" with grass slow
« Reply #2 on: March 13, 2016, 05:56:51 AM »
Tried the distance falloff, but since it's not the detail grass version, it looks patchy. and I don't know how I would use LOD,I'm already using the grass for (Large) areas.

SR1351

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Re: "Transforming vertices" with grass slow
« Reply #3 on: March 13, 2016, 06:36:06 AM »
Okay I just tried Vray RT, and it loads it instantly, why does "Transforming vertices" take forvever with Vray adv? is this a bug?

GL3654

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Re: "Transforming vertices" with grass slow
« Reply #4 on: March 13, 2016, 12:56:07 PM »
could you share your scene ?
just with camera , lights and the problematic grass distribution stuff ?

i tried something similar... large grass preset on a plane 300m (approx. 980 feet) in depth, filling the whole screen...

and it starts so fast that i can't even say how long "transforming vertices" took....

i'm on windows 10, max 2014 SP5, Vray 3.30.04, ForestPackPro 5.03b and have a really old i7 machine .... 2.8Ghz 16 GB ram


SR1351

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Re: "Transforming vertices" with grass slow
« Reply #5 on: March 13, 2016, 05:57:22 PM »
could you share your scene ?
just with camera , lights and the problematic grass distribution stuff ?

i tried something similar... large grass preset on a plane 300m (approx. 980 feet) in depth, filling the whole screen...

and it starts so fast that i can't even say how long "transforming vertices" took....

i'm on windows 10, max 2014 SP5, Vray 3.30.04, ForestPackPro 5.03b and have a really old i7 machine .... 2.8Ghz 16 GB ram

The scene is really huge to send.  But I just figured it out! But I have no clue how to fix it. It renders instantly with "Boundary Checking" set to point, but set to "Edge" as to what I need, it takes FOREVER! What is the issue here, is it a bug? how can it be fixed? This is costing me a fortune to render because of the loading of this grass with Edge turned on.

That is why it rendered instantly on GPU, GPU doesn't support "Edge" mode.

GL3654

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Re: "Transforming vertices" with grass slow
« Reply #6 on: March 13, 2016, 06:38:38 PM »
Ok, I think now I can kind of reproduce your problem.....

transforming vertices while in edge mode is a lot slower than point mode here as well.....

But it seems to extremly depend on your exclude shape's complexity.... (assuming that you are using shapes to exclude)

in my tests it turns out that a complex shape with a lot of vertices slows down the "transforming vertices" process a LOT....

if using shapes, try to reduce point count of these shapes with the "normalize Spl." modifier.  then repick your shapes.

in my test i reduced "transforming vertices" time to appr. a quarter compared to non-optimized shapes.

another thing could be the polycount of your distribution surface itself...

try to distribute your vegetation on low res geometry which isn't renderable.

i know this approach can be a fight when trying to match low res boundaries as close as possible with hi res.... but it should speed up...

edit: another thing i remember : you said it's a golf course you're working on.....
do you use only max-native geometries / shapes ? or did you import shapes/nurbs/whatever created in another program?
i had a lot of trouble in max when using geometries coming out of cad-software... i can't explain why but sometimes max doesn't like foreign geometries.

do you have the same issue when creating a fresh max scene with the same scale using low res geometry created in max?



let me know if this works for you.

regards
« Last Edit: March 13, 2016, 06:53:50 PM by GL3654 »

SR1351

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Re: "Transforming vertices" with grass slow
« Reply #7 on: March 13, 2016, 07:06:22 PM »
These are fresh rebuild scenes in max, Also I don't really use so much Splines to edge the grass, it's just on the geometry itself. Geometry has to be detailed for all the contouring, but isn't crazy detailed my no means.  I still don't understand why edge mode is taking so long. I remember before edge mode there was that trick to use finer grass around the edges and larger patches for over all, I bet doing it that way would still load instantly, something is just not right with edge mode.

iToo

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Re: "Transforming vertices" with grass slow
« Reply #8 on: March 14, 2016, 08:37:35 AM »
Edge mode requires more computing time and memory, because each grass patch near the edge must be evaluated. And yes, processing time depends of the area size and the spline's complexity.

But as far as i remember, we have not introduced changes in FP5 that would affect this.
I would suggest you render a test scene with FP 4.4.1 and compare. If there is a large difference, please send us the file and we'll check it.
Carlos Quintero
iToo Software