Author Topic: Exterior lighting for CGI Architectural  (Read 6121 times)

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Offline jbomb

Exterior lighting for CGI Architectural
« on: March 08, 2017, 03:39:57 am »
Hi Guys,

I'm far from an expert and I could really do with some help/guidance.
I have started to play around with exterior architecture (I'm finding the interior mode great and I'm getting some pretty good results) I cannot seem to get a realistic looking lighting setup for my buildings. I have played around with all presets and started to delve into the HDRI editior. Whilst I can get my renders to look ok they just don't seem to have the realistic look that I'm after. I have attached an image from google as this gives a good idea of what I am trying to achieve. I have not produced this image and it's purely for reference. I assume this has been produced in Vray as it has 'the look' I have then attached an image I have produced (the white one). This has had some test PS work done to it so Isn't obviously a pure KS render.

Do you guys have any templates or setups that I can use to try and get more of a realistic finish?

Any advice would be great.

« Last Edit: March 08, 2017, 07:35:53 am by jbomb »

Offline mattjgerard

Re: Exterior lighting for CGI Architectural
« Reply #1 on: March 08, 2017, 06:20:34 am »
What sort of HDRI are you lighting this with. HDRI is certainly the way to go, but you need to use one that mimics the environment your scene is in. So, for exterior, you wouldn't use one of the black and white studio images. There is color bouncing off everything in the real world, so your HDRI needs to have that color as well.

I think you are off to a good start, the other thing that catches my eye is the greens are way over saturated. If that hyper-real look is what you are going for then great, but if you really look out in the real world, colors are much more muted than we think. The cartoony look the rich saturated colors give your image might just be one small part of why its not looking the way you want. There are many others, hopefully more people will chime in.

I'm always a fan of some small amount of depth of field, even in outdoor scenes, so that might help too. Think about composition of the shot, and how the angles of the house are moving away from you, is the camera lens too wide? Try to mimic real world settings whenever you can.

Keep posting more revisions, will be neat to see what else you come up with!

Offline jbomb

Re: Exterior lighting for CGI Architectural
« Reply #2 on: March 08, 2017, 07:35:02 am »
Hi Matt,

Thank you for the reply and your comments, really appreciate you taking the time to feedback. Totally agree on the over saturation front. I think if I'm honest I'm trying to overcompensate for the fact I'm not really happy with the results.
I used the forestroad HDRI as this seemed to give me the best look. It's things like the beautiful reflections on the windows of the supplied image that I'm struggling to re create. I assumed that using a window material would help with this but my results just seem dull and black.
I will replace my image with a slightly tweaked image as I don't want my poor PS skills to get in the way of the KS rendering element.  Thanks again.
« Last Edit: March 08, 2017, 07:37:01 am by jbomb »

Offline mattjgerard

Re: Exterior lighting for CGI Architectural
« Reply #3 on: March 08, 2017, 08:32:29 am »
That's a good idea. Let us see what you are getting directly out of KS, then we can better know what is going on.

One other thing I was thinking was more about the camera settings, I'll bet you are at about a 35-45 mm lens in the camera settings. I've found that those settings can and do produce an unrealistic perspective. I usually will bump it to 85-100, then back the camera off using the distance slider to get my framing.

Granted that theory has been learned in other 3D apps (Cinema 4D for me) but so far as I'm into KS, it seems to hold true here as well. Especially for larger models such as a house.

And yes, you are getting great reflections in the windows. Also something to remember, and one of the hardest things to tweak, is that in the real world nothing is perfect. Surfaces are full of imperfections, so the windows, the white stucco, all will have various noises that will break up the light and the reflections.

 In the other image that you posted, the brick house, the brick would look really fake and unrealistic if it wasn't for the dappling effect of the light being shone through the trees. The tree shadows really sell it, and add that varigated random dappling effect that breaks up the surface so it doesn't look so even and perfect.

Keep going, its fun to see renditions!

Offline Will Gibbons

Re: Exterior lighting for CGI Architectural
« Reply #4 on: March 16, 2017, 09:01:10 am »
I have to agree with Matt on some topics here. I don't think lighting is the reason your images aren't as realistic as you'd like.

- Add imperfections with bump and roughness textures.
- Reference photographs and grade your final renderings to match.
- Making sure your colors are correct will be huge.
- Use larger HDRIs ... the one you're using from the default library is pretty low-res. That's not going to help out.
- Also, the one you're using (forest road) I think isn't exposed the way your renderings are... with the blue sky and all. There's a disconnect. If these were photos (not renderings), you'd want each photo metered in a similar fashion. Expose for the house and the sky is going to be more blown out and washed out.
- Also, the foliage looks too sharp. To get a photo where everything is that sharp (no depth of field), your exposure would have to be pretty long. If that were the case, a subtle breeze would cause the leaves to have some motion blur... You can do this if they're geometry in KS, otherwise, if they're a photo, you'd have to use some Photoshop magic.
- If windows are too dark, try increasing ray bounces and make sure global illumination is turned on.

In short, I think there are many subtle things that you could do to improve the shots, but it's going to require a pretty strong understanding of photography to understand what to do.

Good luck!

Offline mattjgerard

Re: Exterior lighting for CGI Architectural
« Reply #5 on: March 16, 2017, 12:03:13 pm »
All great points by will. I tend to get stuck in the idea that I want to get it all perfect in the renderer and totally forget that there is much to do in photoshop that can take the image to the next level. I was reading another post about contrast and black levels. Your render doesn't have any areas that drop to 100% black, in a real image there would be in the shadows.

So, just for fun take whatever image you have into PS, play with levels, curves and contrast and see if it gets you closer. then you can go back into KS and make other adjustments knowing what you can tweak in PS.

This is fun. I need to get a personal project going so I can practice what I preach :)