How to make walls visible in render but invisible to light?

lilweep

Is there a way to allow light to pass through walls/objects but still have them visible in render?

Leana

I don't think it's possible if you use Iray.

Phatmartino

I hate to ever give advice that costs money, but https://www.daz3d.com/iray-ghost-light-kit-3 was a game changer for me... It allows light sources of several kinds that illuminate while the source is invisible, so you can just put it inside the room. This could be done for free by using emissive shaders on Primitives and setting the Surface's Cutout Opacity to something minuscule, like 0.0001 (or use a solid black image for the Cutout Opacity and leave the opacity value set to 1.0) You could apply the Emmissive Light shader that comes with Daz Studio to a Plane for uni-directional, Sphere for multi-directional light, etc... Ghost kit is pretty cool, though as it has God Rays, volumetric stuff, color options, etc.

lilweep

phatmartino said:

I hate to ever give advice that costs money, but https://www.daz3d.com/iray-ghost-light-kit-3 was a game changer for me... It allows light sources of several kinds that illuminate while the source is invisible, so you can just put it inside the room. This could be done for free by using emissive shaders on Primitives and setting the Surface's Cutout Opacity to something minuscule, like 0.0001 (or use a solid black image for the Cutout Opacity and leave the opacity value set to 1.0) You could apply the Emmissive Light shader that comes with Daz Studio to a Plane for uni-directional, Sphere for multi-directional light, etc... Ghost kit is pretty cool, though as it has God Rays, volumetric stuff, color options, etc.

I mainly just wanted to use an HDRI lighting within a closed space.  "ghost lights" may be my only alternative.

i typically just set up emissive primitives with low opacity as you described.

 

DrunkMonkeyProductions

It is possible, but may not be particularly practical.

The way i did it is similiar to how "ghost lights" work, emissive surface and reduced opacity.

In the case of the attached examples, i'm using 6 planes with iray materials and only lighting with an HDRI.

in the first image(hdri only4), the opacity of the four walls is set to 0.5 with emission color white(1,1,1) and the luminance set to .01.

in the second image, i've turned off the walls.

the third image is with the luminance off.

 

with a bit of tweaking the brightness of the hdri or maybe a change to the exposure settings, you could possibly get better results than these.

This is purely for proof of concept.

 

 

 

lilweep

interesting

WendyLuvsCatz

you can with Octane and there is a free DAZ studio tier

mwasielewski1990

lilweep said:

Is there a way to allow light to pass through walls/objects but still have them visible in render?

Render using Iray Canvases. Render the desired actor w/lights on a separate node, than render the walls on an other node and combine them in any photo editing app.

Just type in google "Daz3d Iray Canvas tutorial", there are numerous videos and pages explaining how it works, It's really simple.

 

Daventaki

PaperTiger has several sets in her Rendo store that has an HDRI XRay Camera Preset which allows HDRI light to into fully inclosed rooms.

https://www.renderosity.com/mod/bcs/?uid=452517

lilweep

mwasielewski1990 said:

lilweep said:

Is there a way to allow light to pass through walls/objects but still have them visible in render?

Render using Iray Canvases. Render the desired actor w/lights on a separate node, than render the walls on an other node and combine them in any photo editing app.

Just type in google "Daz3d Iray Canvas tutorial", there are numerous videos and pages explaining how it works, It's really simple.

The room still wouldnt be lit by the HDRI though?

lilweep

Daventaki said:

PaperTiger has several sets in her Rendo store that has an HDRI XRay Camera Preset which allows HDRI light to into fully inclosed rooms.

https://www.renderosity.com/mod/bcs/?uid=452517

the X-ray cameras just use a bunch of differently angled section planes (i assume positioned behind the camera to avoid the look of clipped walls).  It's still not ideal because light will only enter through the sectioned areas, and not 360 degrees.  But I guess it's another option.