Thought I should do a quick tutorial on how I use these HDRi Skydomes I’m selling. Note that this is just one of many possible workflows, and there are probably lots of tricks I’m missing and even things I do completely wrong. I should also say that I work mostly with still images, not animations.
1. Here is a typical architectural scene. It is a model I made of Waro Kishi’s Fukaya house in Japan that never really went anywhere.
2. I use a gamma 2.2 workflow together with reinhard color mapping, so not strictly LWF but shares some of the advantages. I don’t want this to turn into a LWF tutorial or discussion, but this post on cgpov.com pretty much sums up how I feel a gamma corrected workflow helps us as visualisation artists.
The reinhard color mapping helps to control burnt out (overexposed) areas. Screenshot of my color mapping set up: The burn value of the reinhard color mapping typically ranges from .75 for an exterior to 0.05 for an interior. You need to experiment with the value until you gain control over the burnt out areas. Here is an example with a camera pointing at the HDR sky:
For the final render, I use the Vray Frame Buffer, and add a slight s-curve to the output to compensate for the lack of contrast that the gamma corrected workflow introduces:
3. Add a vray dome light and load the exr/hdr using the max bitmap loader. Set the mapping type to environment/spherical. If you are using .hdr files, you can use the vrayHDRi loader instead. It makes no difference whether you use the bitmap loader or the vrayHDRi loader, the vrayHDRi adds a bit more control in that you can control the render multiplier independently from the viewport multplier. Set the output of the .exr to 1 and the vraylight multiplier to 1. If your hdr/exr has no alpha channel it seems you can save quite a bit of memory while rendering (approx 200mb in my case) if you load the exr/hdr as realpixel float rgb rather than the rgba option.
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4. To rotate the HDR you need to enter a U offset value from 0-1, so to rotate 180 degrees with would enter 0.5, 270 degrees 0.75 etc.
5. Add a vrayphysicalcamera, and set the aperture and shutter speed to something that would work for a typical outdoor scene, like F4, 1/200th & ISO 100. Remember that you are in effect using a completely manual camera, there is no ‘P’ or automatic mode so you need to experiment with different exposures until you get a good result.
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6. Hit render and see what you get. If it looks too dark/bright I tend to adjust the bitmap’s output rather than the vraylight multiplier, so that I can have a couple of ready setup HDRi’s ready to drag and drop onto the dome light. In the examples below I use an output value of 1.5.
Hello Peter,
Thank you for this very much. Recently, I gave a try at this. But instead of using a hdri I used very high resolution image. Thanks to your settings I did some test and it does really work nicely.
My only question would be, how does you Vray sun look yellow. Mine still tends to be white in color. I specially note this in your “Line house” or “Sail house renders”, that the environment is very beautiful due to the hdri with that the sun in day light renders also looks a nice yellow. Would like to know how to achieve that.
Thanks in advance.
If its low enough in the sky it should be yellow enough, plus you can try increasing the turbidity value of the sun
Hello Peter,
Thanks again. It’s around mid-day sun. I will try working with turbidity.
Works great. I worked up the S-curve a bit and it came out well. I plan to buy couple of hdri’s from your site soon. Presently, the tut’s have done a tremendous help. I simply increase the multiplier of the Vray-dome when using jpg’s. Which I thin won’t be necessary when using your hdri.
can you point out what is that s-curve you mean and where ?
@hany the 5th image
Hi there Peter,
Sweet tut, I’m just trying to figure out what’s the big advandtage of using a vray domelight instead of just popping the background into the environment-slot. Which in my tests renders alot faster?
Very good stuff as always Peter, thanks.
Though i cant find the way for “vrayHDRi loader”, using Vray HDRI map i don´t get an options dialog box nor nothing….
@nic better sampling, and you should get better direct light from the sun (crisper shadows) although tbh I havent tested this extensively
@pep not sure what you mean, vrayHDRi loader can only load .hdr files
Yes sorry, i thought your tut.’s capture of “open EXR” was the VrayHDRI loader, and was the bitmap one!!
Best regards,
Hi Peter,
I just have a quick question regarding HDR dome lighting -
I have several HDR files that I would like to use, but when I use them, my scene is really dark (especially with the multiplier at 1) , so in order to compensate I adjust the shutter speed, which isnt a problem as such. If I adust the shutter speed to 20 it works, but then say I switch to lighting with the vray sun sky the exposure is way off. Obviously the HDR is too dark, but is there any accurate way to use HDRs so that it simulates the sun intensity?
I try to use real world values as much as possible for other lights, so it would tie in nicely if I could set up the HDR dome light accuratley without guessing the power of my lights.
Is this problem also down to poor HDR quality? When viewing them in Bridge, they look dark, even though they are mid day sky HDRs.
I hope that makes sense!!
Cheers, Deano
Hi Peter
Just wondering, for the above tutorial, do you have sample files for the model and HDR ? I can’t seem to see them.
Thanks
Niall
Hi Niall, sorry, not for this tutorial
Hello Peter,
I was wondering if you gamma correct you HDRI (2.2)? or just leave it at 1
mn, gamma should be left at 1 for hdr images