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Author Topic: How to find the error forest quickly ? I get this after local render.  (Read 570 times)

cc8boy

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Hello everyone,
   I was testing render a forest today. The render speed became extremly slow suddenly. It showed me this(see the attachement) after rendering. Then I checked the forest objects one by one. (Open the modify pannel and select the stats icons one by one.) I can't find the error in all the forest object. Why the error appear after render ?

1. How to find the error quickly except check the forest stats windows one by one ? MAXSCRIPT?
2. What cause the problem ? :'(

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Michal Karmazín

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Re: How to find the error forest quickly ? I get this after local render.
« Reply #1 on: March 22, 2016, 09:23:45 AM »
Hi,

That's just a warning message informing you, that has been reached the actual view-port limit and not all items will be shown in the view-port.

I would suggest you to check you are using presets that are meant to cover a large area(s). These will create fewer instances and are less taxing for the renderer. For both the Lawns and Meadows presets you will see there are two versions for each type, one with a (detail) suffix and another with a (large) suffix. Unless you're filling a small area, I'd pick the large ones.

To improve the overall render performance, an option would be to reduce the GI quality for the grass. To do it, select the Forest object->right click->V-Ray properties->set GI subdivs multiplier to 0.1 (or other lower value). This change may cut the final render time by 30%.

Also, some material simplification will drop down the final render time significantly. The grass material used in our presets is quite complex to give a nice realistic look but it can be simplified which will give you shorter render times. To cut render-time, you can remove VRay2SideMtl from materials and use only the front VRayMtl. Grass will look less realistic, but you'll notice a great performance improvement.

Please don't forget to double check, if the Dynamic memory limit is set properly (you can set Dynamic memory limit to 0 to remove any limit in that case, your renderer will take as much memory as needed). This parameter has a great impact in performance when rendering complex scenes.

Hope that helps.

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cc8boy

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Re: How to find the error forest quickly ? I get this after local render.
« Reply #2 on: March 22, 2016, 11:38:27 AM »
I didn't use the resource of the library.
This was the grass I made of three clumps of Forest Object. Each clump which was forest object was made of 10 independent models.
10 models ----> three clumps forest objects (size check mode,all material=undefined) ----> a large Forest object (edge check mode,all material=undefined, camera limit)
They were all in one scene and kept all connection.



The material is

Bitmaptexture ---> forest color (override) ---->forest color (from map) ---> Vraymtl (No 2sided material)

The grass forest nodes were merge from another scene. These nodes were rendered so fast in the scene that I merged from. All the render setting were the same as the last scene merged from.


Is the problem in the forest object or the material from sample objects ?
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Michal Karmazín

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Re: How to find the error forest quickly ? I get this after local render.
« Reply #3 on: March 22, 2016, 01:02:41 PM »
Hi,

Would you mind to send us that scene (containing problematic Forest object(s)) through WeTransfer to support@itoosoft.com to analyse it here? Also please specify used 3ds Max / renderer releases. Thanks in advance.

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cc8boy

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Re: How to find the error forest quickly ? I get this after local render.
« Reply #4 on: March 22, 2016, 01:19:16 PM »
I will send my scene to you later. But may I ask you one major question ?

1. Many big clump with edge detection mode in forest object. Edge mode in animation rendering.
2. Big clumps combine with small clumps in point detection mode. It's the old trick of making clean edge of grass.

Which way will render faster ? I will even care a few seconds faster. Does it render slower in Edge mode than the old trick ?
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Michal Karmazín

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Re: How to find the error forest quickly ? I get this after local render.
« Reply #5 on: March 22, 2016, 04:02:13 PM »
Hi,

Thought there shouldn't be a big difference and it'll depend on many factors (on how large areas the detailed preset will be used, its density and so on) in several situations using the Edge Boundary Checking might be slightly faster (as less items will be distributed as the "trimmed part" is treated by the V-Ray render engine as a kind of "Matte object" internally), but in some scenes it can be vice versa.

Let me add, that there is no general rule about the size of used clumps, as that mainly depends on how complex models are used, but distributing very high poly-count items might be quite memory consuming.

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cc8boy

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Re: How to find the error forest quickly ? I get this after local render.
« Reply #6 on: March 22, 2016, 05:56:46 PM »
Many Many thanks for your reply. So it is. Now I understand edge mode acturally turn the elements into "Matte Object".
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