Black material preivew with a whole lot extra.

[davidlouis]

I recently tried to create a realistic material for roof sheeting using a diffuse and displacement map.

After I had set up the material in the material window, I hit preview and noticed that I was getting a black material preview. ???. After reading a bit on this forum, it seems that other people are experiencing this too…

At first I didn’t worry too much about it as I have experienced something similar in the previous versions of Vfs particularly when trying to create realistic water and I know that the displacement effect can twist things up a bit anyway depending on the displacement values… I did a test render and all seemed to be well but I thought the displacement effect needed to be a bit more intense so I thought I’d up the global value to do this in the vray options window… that’s when strange things started happening.

On going back to the Vray options window, I noticed that I’d lost the ability to input / change any values in any tab… and when I tried to click on the displacement tab and edit the settings, things just jumped around like crazy. Even if I created a new file within the same instance of sketchup, it seemed like the loss in functionality of the Vray options windows was continuing…in fact the only thing that would help was to save the file and to completely shut down sketchup and reopen the file from scratch in a new instance of sketchup. Functionality in the Vray options window would then return, although if I tried to preview the material again in the material window, the same problem would happen again… but here is where it gets even stranger…

When I shutdown the problem sketchup, even though it closes down completely, if I look in my windows task manager window, the sketchup process remains…. and saps about 50% of the cpu usage… When I start up a new instance of sketchup, the ‘ghost’ process remains in the list and keeps draining the cpu usage… so when it comes to rendering in vray, things are a bit slow even for menial test renders at low res… and if I keep on creating the problem as outlined above, more ‘ghost’ processes keep on appearing every time I restart sketchup…each time sapping a little more cpu usage until soon the whole system freezes up…

This is obviously not normal and something needs to be done… so if anyone can offer some advice or a solution, I would appreciate it a lot. I reckon this is one for the Vray bug hunters out there so that it can be patched in the next release which is hopefully sooner rather than later.

I have included my bug file and texture maps I’m using to create the displacement material… hopefully you can create the same problem scenario and at least give me the comfort that I’m not crazy…

http://www.4shared.com/file/24148041...ement_bug.html

I’m using the latest version of sketchup (7.1.6860) and Vfs (1.48.66) on WinXP pro sp3.

Please help…
Thanks….Dave

[dkendig]

Re: Black material preivew with a whole lot extra.

Sounds like you ran in to quite the patch of trouble Dave. Let me start by saying, no you're not crazy, rest assured, you are encountering a couple bugs.

Bug 1: Materials that use displacement can not be previewed properly at the moment. The preview render will start, and then "something" happens, and it never stops rendering. No buckets appear in the preview window other than black ones, and it just sits there thinking forever.

Bug 2: You can't close SketchUp if V-Ray is busy. If V-Ray is chugging along in the background, SketchUp appears to be powerless to stop it. So rather than a crash, this would be the complete opposite, V-Ray lives on, even though the environment that it lives in is completely destroyed. (Sort of like a zombie) Very odd, and if you're not aware that this is happening, you'll run out of system resources very quickly.

Both of these issues are rather nasty, and we're still working on resolving them. The displacement preview issue in particular is quite puzzling. In one build, everything was fine, the next build... mysterious zombie V-Ray appeared. I've spent a good bit of time trying to track this down so far, as well as the other developers, and we just can't seem to find the cause of this (yet).

So in the meantime, as a work around, if you try to preview a material that has displacement, and you encounter the issue where the preview never finishes rendering, just select another material in the V-Ray Material Editor, and the preview render will be cancelled. (We set it up so the preview only renders for the currently selected material. If you change the selected material, the render for the previous material will be cancelled). This should help prevent zombie behavior as well, because there won't be a render going on behind the scenes, holding up the whole show.