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Author Topic: Issue with pivot and placement in RT/render output  (Read 1173 times)

Sebastian

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Issue with pivot and placement in RT/render output
« on: April 19, 2014, 05:09:01 PM »
Hello,

I have an issue with the distributed placement of a vray proxy. I tried to fetch all useful information on the following screenshot:



The vray proxy is a tree. The pivot is placed at the bottom end of the trunk in its center (see fv and rv), but this is not also the center of the proxy itself if seen as a box. After distributing this proxy over a mesh I added two circle splines for distribution of some needles (large circle) and for excluding distribution of grass (small one). Now I tried to place these two areas as exact as possible where the trunk should touch the ground by checking the result in the RT window (camera view), which looks ok so far. But at render time the tree is placed with an offset which I cannot explain.

My thought is that this is the offset between the actual pivot x/y and the calculated center x/y of the vray proxy box, which means that the Forest Proxy (thin box in this case) marks the center of the vray proxy and not its pivot? Well, that would be a problem for me ...

Then I found the "Center Displacement" function which corrects this issue for billboards but is also available for custom objects. To solve my problem I would need another displacement spinner for the y-axis. But even with that it would be hard work to figure out the two values for each object that I want to use in the scene ...

Any hints are welcome  ;D

iToo

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Re: Issue with pivot and placement in RT/render output
« Reply #1 on: April 20, 2014, 09:32:45 AM »
I tried to reproduce the problem: in the attached image i used a V-Ray proxy in a Forest object, which is used as excluding area for the grass. But the alignment seems correct, both in viewport and render (Max 2014, FP 4.2.2, V-Ray RT 3.00.05).

Please send us a test scene to support@itoosoft.com. We'll check it.
Carlos Quintero
iToo Software

Sebastian

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Re: Issue with pivot and placement in RT/render output
« Reply #2 on: April 20, 2014, 06:11:07 PM »
File sent.

iToo

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Re: Issue with pivot and placement in RT/render output
« Reply #3 on: April 21, 2014, 09:10:42 AM »
Thanks for the file. I can confirm the problem: it's not related with V-Ray proxies or the pivot. The item's position doesn't match with the viewport preview, but it happens only with certain combination of Collision Checking, Surface and excluding areas.

We are investigating the bug. As workaround i suggest you switch Forest to Custom Edit. This mode keeps the distribution shown on viewport and matches with the render.

I apologize by the inconveniences.
Carlos Quintero
iToo Software

iToo

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Re: Issue with pivot and placement in RT/render output
« Reply #4 on: April 21, 2014, 10:28:40 AM »
Ok, we've found what it's happening:

Forest is using different densities on viewport and render, because the limit defined at Display->Max Items. So, the result afer applying Collision Checking changes as well.
Increasing that limit (i.e. to 500k items) should solve the problem. Anyway, that also will increase the processing time on viewport, so i suggest you adjust the density values before, or use the Custom Edit trick described in my previous post.
« Last Edit: April 21, 2014, 10:36:34 AM by iToo »
Carlos Quintero
iToo Software