Interior Mode + HDR Lighting/Reflection

[bdesign]

*EDIT* Updated workflow in reply #4 below

I was viewing the awesome "Sci Fi Environment" image by @_davidschultz_ , found here:  https://www.keyshot.com/forum/index.php?topic=13080.0 , and reading his subsequent comments about wanting to have HDR lighting and/or reflections visible in an enclosed space, Interior Mode render, and it got me to experimenting. My example scene setup is a KeyShot cube primitive, scaled to a very large room size (75x50x12.7 ft), split into 6 surfaces with the Geometry Editor, with 6 overhead IES lights, and some large reflective spheres. For any surfaces through which HDR light and/or reflection was desired, I connected a Surface Backside Mask>(Input)Color To Number>(Opacity)Diffuse material. The "Output From" and "Output To" parameters act as a sort of "filter" for the HDR light and reflections, respectively, while maintaining and "blending" with properties of an enclosed interior render. The test renders below represent a few of numerous possible combinations of the C2N OF/OT to achieve various looks/moods. The specs for each are as follows:

1. HDR=OFF("All Black", Contrast=0, Brightness=0), Overhead Lights=ON

2. HDR(Light Only, From All 4 Sides)=Ambient Low ("All White", Contrast=1.7, Brightness=7, colorized @ 3100K to match overhead lights temperature). Overhead Lights=ON. C2N(All 4 Walls): OF=.7, OT=1

3. HDR(Light+Reflection, From Right Side)=Sunlight Low ("Dosch-Studio2_2K", Contrast=1.7, Brightness=7, colorized @ 4100K to simulate direct sunlight). Overhead Lights=OFF. C2N(Right Wall): OF=1, OT=.98

4. HDR(Light+Reflection, From Right Side)=Sunlight Low ("Dosch-Studio2_2K", Contrast=1.7, Brightness=7, colorized @ 4100K to simulate direct sunlight). Overhead Lights=ON. C2N(Right Wall): OF=1, OT=.98

5. HDR(Light+Reflection, From Right Side)=Sunlight Bright ("Dosch-Studio2_2K", Contrast=1.7, Brightness=7, colorized @ 4100K to simulate direct sunlight). Overhead Lights=OFF. C2N(Right Wall): OF=0, OT=.7

6. HDR(Light+Reflection, From Right Side)=Sunlight Bright ("Dosch-Studio2_2K", Contrast=1.7, Brightness=7, colorized @ 4100K to simulate direct sunlight). Overhead Lights=ON. C2N(Right Wall): OF=0, OT=.7

Overhead Lights(ON): Flat_moon_680_down_LED_GI_12850209_IES.IES, Multiplier=15, Radius=1

Cheers,
Eric

[Will Gibbons]

This is interesting.

To simplify the results of your finding, you were able to get reflections of HDRI without any light being provided by the HDRI, correct? And further, if you did want to have some light provided by the HDRI, you were able to choose which direction it came from by controlling each face of the enclosing cube. Is that correct?

And the main benefit (other than further control over lighting) is that you can use interior mode to render the scene?

Interesting.

[DMerz III]

 

WOW! This opens a whole new world of possibilities. Granted they were always there, but you've shown us the way once more.

Thanks Eric!

[bdesign]

This is interesting.

To simplify the results of your finding, you were able to get reflections of HDRI without any light being provided by the HDRI, correct? And further, if you did want to have some light provided by the HDRI, you were able to choose which direction it came from by controlling each face of the enclosing cube. Is that correct?

And the main benefit (other than further control over lighting) is that you can use interior mode to render the scene?

Interesting.

Thanks, Will. That's pretty much it in a nutshell, but I've done some more testing and come up with a bit more streamlined and concise workflow which allows more control of the isolation/blending of HDRI reflections, HDRI ambient light, and HDRI direct light (or direct "sunlight" in my example) within an enclosed space. I'll post an update after getting a few test renders done.

WOW! This opens a whole new world of possibilities. Granted they were always there, but you've shown us the way once more.

Thanks Eric!

Thanks, dmerziii, kind of you to say that You're welcome!

Cheers,
Eric

[bdesign]

Here is an updated workflow with more concise, simplified examples. I've added an additional node to the mix (Ground material) to allow for HDRI reflections only, without light contribution. The basic flow is a Surface Backside Mask>(Input) of two Color To Number nodes, one each>(Opacity) of a Diffuse material and Ground material, with the Diffuse material applied as a Label to the Ground material. The "Output From" and "Output To" of the C2N node plugged into the Ground material control the contribution of "ambient light" and "direct sunlight" respectively; lower values = more light contribution. A value of 1 = no light contribution. The four example images below have the node network applied to the right wall (off-camera), and use the same HDRI Environment (Dosch-Studio2_2K, Contrast = 2, Brightness = 8, Rotation = 90, colorized @4100K) and illustrate: 1. HDRI = None, 2. HDRI = Reflection Only, 3. HDRI = Reflection + Ambient Light, 4. HDRI = Reflection + Ambient Light + Direct Sunlight. All rendered with Interior Mode, GI enabled. Here are the settings for each:

                      HDRI:                                                     Diffuse Material (Label):                     Ground Material:
                      Effect                                                C2N Output From/Output To      C2N Outut From/Output To
                      ______                                            _________________________  ________________________

Image 1      None                                                                     1/1                                               1/1

Image 2      Reflection                                                                  1/.5                                               1/1      

Image 3      Reflection + Ambient                                                  1/.5                                               .9/1

Image 4      Reflection + Ambient + Direct Sunlight                      1/1                                               .9/.9


Cheers,
Eric

[__davidschultz__]

Thank you for doing this, Eric!!!

[bdesign]

You're welcome, David! I learned some new things in the process

Cheers,
Eric