Interior lighting issues

Started by rkulshrestha, October 07, 2016, 03:15:59 PM

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Hi Will

The reference image looks like this


Will Gibbons

I played around with a simple model I made, but ran into some strange scaling issues as well. I think I know what caused it, so if I can fix the issue tomorrow, I'll share the scene.

When working with physical lights in KeyShot, there's a lot to take into consideration. Scale as previously mentioned has lots to do with it. In the example I made, I created a recessed cylinder in a ceiling. I applied a chrome material to the inner surface of the recessed area to act as a reflector. I put a simple cylinder to act as the light bulb, and then applied an IES light to it in KeyShot. Some of the IES light profiles in the KS library are better than others, so try a few out. Or feel free to use IES profiles from elsewhere online. Lastly, I made a piece to cover the recessed light (shaped like a contact lens). In real-life, this would be a piece of frosted glass, but in KeyShot, I used the advanced material to create a translucent material to allow the light to shine through it and dial in the material appearance.

The halo effect on the ceiling you were getting is light that is reflecting onto the ceiling. If you don't want that, your ceiling light should be fully enclosed.

I've attached a screenshot of the test scene I created, as well as the HDRI settings I was using. If I can sort out the scaling issue, I'll upload it for you to play with. I hope this helps a bit.


Hi Will

Thanks for the response. Amazing support!

I started off just trying to get lighting right and reach the quality boyd_747 was reaching. The final render shots on are also amazing, like the previous one I posted.

The last SU scene has 2 large polygon spheres which are lit then hidden to give interior lighting more volume. It's a nice shortcut, but takes away from the realistic effort.

I am rebuilding the ceiling lights following your advice and will check out the effect. In the meantime I have two questions:

Since we can isolate parts with material and move them around in KS, is it possible to save them in a separate folder. That way I could have a ready to use ceiling light for new models.

Second, is it possible to have an HDRI inside an interior? Can I use the HDRI editor to place pins inside the interior? This avoids messing around with above mentioned hidden polygons in the SU model.



Quote from: rkulshrestha on October 14, 2016, 12:46:28 AM
Second, is it possible to have an HDRI inside an interior? Can I use the HDRI editor to place pins inside the interior? This avoids messing around with above mentioned hidden polygons in the SU model.
Hey Raj-

Check out my forum post here: , in which I discuss a workflow for incorporating HDRI lighting and reflections within an enclosed space, Interior Mode render.



Hi Eric

Thanks for the post. I did read this a while ago during my research. What you did was way above my skillset  :D. Any chance you can share the bip file so I can study it more. How did you get those really sharp ceiling lights, even what I did below doesn't match what you achieved.

In the meantime, I set about creating a very accurate ceiling light taking all the advice on board. Chrome interior, concave lens (made out of Sketchup skin and bubble generator) and very accurate circles to prevent light leakage.  The results are much better!

Is my reference image on the previous page a product of extensive Photoshop?



Why don't the IES lights point downwards when I apply them to an object? I have to go and rotate them individually each time.

Will Gibbons

Hi Raj,

To address some of your earlier questions. You don't want to use an HDRI inside an interior, although Eric has found ways to allow more lighting from an HDRI to come into an interior, it doesn't create the most realistic effects. That said, his thread has a wealth of information on the topic, so I recommend reading it again.

Your last example is much improved. It's good to do quick/simple tests until you find predictable and repeatable results, and then go about creating a more impressive/complex scene.

For your last example, you'll want to have at least 4 ceiling lights in the room probably. You can also rely on some light from an HDRI. I suggest using KeyShot's sun/sky HDRI generator, and then rotating your environment so the sun is coming in through the window. It'll make your scene very warm, so I recommend desaturating it a bit for more white light. Next to consider is the materials inside the room. A rough rock material is very diffuse and dark in color and won't reflect much light compared to an interior with white, smooth walls/surfaces. Make sure you're using realistic materials inside your interior. You can also add accent lighting, such as illuminating the floor lamp in your scene for additional light.

Once you've done that, you can add a plane in the ceiling and apply an area light to it and hide it from view.

Your IES lights are based on the direction of the geometry you've applied them to. If you've got a cylinder with a local 'up axis' of -y and you apply an IES profile that uses KeyShot's default 'up-axis' of y, then you'll need to rotate the cylinder 180 degrees to point down.

You asked if your reference images are heavily Photoshopped. I don't think they necessarily are, but each scene has been optimized and well-lit following the rules of the rendering program used.

One of our support members looked at one of your sample scenes and saw some confusing stuff from scaling issues to odd file name extensions.

Can you describe what version of KeyShot you're using and your workflow?
Where are your models from?
How do you import the geometry into KeyShot?
What file formats are you importing into KeyShot?


Hi Will

Its Keyshot 6. Dont know what you men by Workflow though, I haven't been through though those tutorials as yet. I just download  SU models from 3Dwarehouse or from Sketchup

I save the revised SU model after tweaking it and then KS use it to import it. The formats are always skp files.

The odd names are because I am using a rudimentary naming technique in Sketchup Outliner which follows a similar hierarchical system as scene tree does. Also, some of the naming ceremony is native to SU so I don't bother with that in the interest of speed.  I'm getting my feet wet with KS after a long time. I do a fair amount of work in SU. On holidays right now and been spending my time Keyshotting every thing. Once I get good at this, I'm gonna teach a whole bunch of guys. I was an early evangelist which is how I made full member  :)

I'm making some progress as you can see. One of the tricks I was using was applying materials to an object so that other linked surfaces would pick up the same material. You can see the white box on the right side. That has the same color as the light source in the ceiling lamp. It works for an area light, but doesn't seem to work for IES lights.

This one thread as addressed so many issues, I hope others will find it useful.

Cheers Raj


Its getting better. Not as snappy and crisp as the reference image, but an improvement. Thanks Will and Eric.


And a second view. Some stuff outside the window still needs cleaning.