Renderings do not show hdri background

[jp_bernier]

I've been working on this for some time now - It's worked before, but now it won't and I don't know why. I can get all of the lighting and exposure etc to respond, but for the life of me I cannot get the image to have an HDRI background. It just makes the white/light blue sky gradient. Here's a screenshot of my settings. If you need to know what any other settings are at that are not displayed, please reply. I've tried using the Dome Light and the Vray Sun, but they both behave the same (no rendered background).

[Ana Lyubenova]

Hi jp_bernier ,

From what I see on your screenshot:
1. Close the Revit rendering settings dialog, as it has nothing in common with V-Ray.
2. Disable the V-Ray Background image.
3. Once the Light Gen tool finishes generating light scenarios, simply double click on the thumbnail the scenario of which you want to apply. This will automatically enable V-Ray's Dome Light and the image will be assigned to it.
4. If the image appears too bright when rendered, decrease the Dome Light Intensity parameter.

If you want to use Background image, combine it with V-Ray Sun. And if the rendering is too bright, experiment with the Background image brightness as well as with the Camera exposure value (EV).

Let me know if the above helps you solve the issue.

Best,
Ana

[jp_bernier]

Hey Ana, thanks for writing back. The Revit rendering settings were shown just in case any of that mattered (sun vs. artificial lights, etc).

This has gotten complicated. I think something is way broken.

In V-ray Sun, adjusting the intensity and/or the background brightness has no effect and makes no change ranging from 0-100 for either/both settings. Using "screen" vs "spherical" also has no effect. I've tried several different hdri images. Clicking a thumbnail from the Light Gen imports a new background and adjusts exposure and white balance but actually does nothing for the rendered background. (see Render-1 and Render-2 images) Also by doing this, all exterior lights become permanently disabled (even when Disable lights on application is un-checked).

If I use V-ray Sun and the background image, the lights come on fine but no background, just solid light gray with slight ground albedo. However - and this is where it gets really weird. If I step the exposure down to get an evening view... it will never lighten back up. See screen shots.

These are really erratic results so I don't know if you can make any sense of them - maybe I just need to send you the file?

[jp_bernier]

So I tried an experiment. I made a 2nd view, looking at the same thing and rendered it with the exact same settings. You can see in the two attached images here, one is totally dark - but the new view is so blasted out over-exposed it's entirely white. How can this be?

[Ana Lyubenova]

Clicking a thumbnail from the Light Gen imports a new background and adjusts exposure and white balance but actually does nothing for the rendered background.

It doesn't import a background, it creates a Dome Light for image-based lighting with the respective HDR image from Light Gen. Have you attempted to use only Dome Light?

As for the completely white rendering, with Sun Intensity set to 100 and EV set to 5, it is possible to receive an overexposed result. I'm interested to have a look in your entire setup anyway. Are you able to send us the project along with the corresponding assets? We will use it for testing/debugging purposes.

Best,
Ana

[jp_bernier]

Ana, this seems to a machine specific problem. These two renderings were done with the same file, but on different computers. Each computer has the exact same Vray and Revit settings (as best I could tell) applied (except one had Asset Randomize enabled and changed the size of the planting elements). One machine renders the background, the other does not. I know this isn't Autocad obviously, but that software has a way to export a text file of all the system variables so that you can compare and troubleshoot the settings of two files, etc. Do you know if Revit and/or Vray can do this? Unless it's an installation problem (which will be my next step), there's probably just a setting someplace that is blocking the background from displaying.

[jp_bernier]

Update: Un-installing and re-installing Vray did not solve this issue.

[Ana Lyubenova]

Hello jp_bernier ,

Can you run a rendering on the problematic machine, then find the most recent V-Ray for Revit .log file and send it over to us? Logs are normally stored here: C:\Users\<your username>\AppData\Roaming\Chaos Group\V-Ray for Revit 20xx\Logs
From what you described, it could be that the path to the hdr file cannot be found. If you store it on a shared drive, you need to add the path to it in the Settings/Paths & Sharing tab (link here).

Yes, you can export a .vrscene files from both machines and compare them. The export button can be found after expanding the Render toolbar panel.

Will you be able to send us the model? If not, we could organize a remote session.

Best,
Ana

[jp_bernier]

Hi Ana,
I think I've figured this out. In the Log file there was an error about Adaptive Lights causing an (unspecified) asset to not render correctly. I'm assuming this asset was the background image since everything else rendered fine. When I was confirming the paths were set up correctly per your suggestion I noticed that in the V-Ray Settings --> Paths and Sharing --> Settings, the box was ticked for "Sharing" and after I changed that to "Default" I was able to purge everything out. This is the step that fixed the problem. There must have been some old crusty asset in there mucking things up, but I don't know why it wasn't affecting things on my other computer? Regardless I don't think I would have discovered the purge option had I not followed your tip to look at the paths, so thank you! Btw, your glasses are outrageous, I love them! Cheers!

[Ana Lyubenova]

JP, good to know that you've found a workaround. Let us know if you experience any further issues. And thank you for the sweet compliment!

Best,
Ana