Light from outside room

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ntxdave
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Light from outside room

Post by ntxdave » Fri Jul 01, 2016 4:54 pm

I am trying to learn how to use Twilight Hobby better. I am trying to understand how to achieve lighting from outside. In this render,
I want light to shine through the window into the room and for the background image to be brighter (more like the way it looks in SketchUp).
RoomRender v1.PNG
RoomRender v1.PNG (270.74 KiB) Viewed 11361 times
I have been told that I can make the panel that contains the background image an emitter but after looking at the
documentation and tutorials, I do not know how to do that. Any/all advice on how to move forward would be greatly appreciated.

Chris
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Re: Light from outside room

Post by Chris » Sat Jul 02, 2016 1:41 am

The first thing is to always use Architectural Glass for your windows. This will prevent undesirable refraction and shadowing and let in light.

Making your background an emitter won't work to cast light into your room. You are better off using a spotlight shining into the window (which is what I recommend for getting light in through the window). However, if you just want the background to be brighter, assign the Emitter Template to the background and the set it to Fake Emitter (that's important!).

ntxdave
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Re: Light from outside room

Post by ntxdave » Sat Jul 02, 2016 2:04 am

Wish I would have seen your reply before creating some new renders but I will share one anyway since this is a learning experience. Here is what I just finished generating.
Room v2.jpg
Room v2.jpg (166.4 KiB) Viewed 11348 times
Chris, I will give your approach a try tomorrow (I hope). I really appreciate this as I want to learn to do things better. When I add the spotlight, do I just kind of put it in "mid air" and then aim it the way I want it to light up the room? At lest I did get a little reflection of the lamp in the window (for what ever that is worth). Again, IMO, learning is an iterative process of trying different things until your get it the way you want it.

Once again, I really appreciate the feedback.

tuna57
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Re: Light from outside room

Post by tuna57 » Sat Jul 02, 2016 5:36 am

Dave, Have to apologize for steering you wrong about the use of emitters. Was certain I did a few test renders like I described to you. Either I pulled off the impossible or my memory is shot ! Posting a couple of pics that might help get you closer to where you want to go. He's another way you might try setting things up.

Made a simple "room 12' square. put a "window" in it. Set up my scene and adjusted shadow settings to get shadow through window the way I wanted. To make it easier to adjust shadows I make one wall a separate group on it's own layer and hide it while setting things up.Textured my outside image on a big rectangle and moved it around so it wouldn't block the sun coming in the window but look o.k. when looking out window. Window is architectural glass-common as Chris said.

Sun is enabled and put 2 point lights inside of the room. Made the outside image a fake emitter power at 100 watts.Rendered on easy 9. 5 passes exposure set at 2.0

Hope this helps.
Attachments
room test.jpg
room test.jpg (699.41 KiB) Viewed 11343 times
room test2.jpg
room test2.jpg (139.39 KiB) Viewed 11343 times
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Fletch
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Re: Light from outside room

Post by Fletch » Sat Jul 02, 2016 1:17 pm

Tuna57 has given a very nice example here - :rspkt:
My only comments would be: The missing front wall shown in the screenshot would actually be there when rendering. This would give more accurate lighting.

IMPORTANT: Your camera in Twilight Render is based upon the physics of light and cameras in real life. So increasing the exposure of your rendering in the rendering dialog window under "Tone Mapping" is very important... just as a real camera increases the exposure when taking indoor photos.

This question is literally the most common question over the years, which makes it also the oldest/first FAQ question. So:
1. PLEASE WATCH ALL VIDEO TUTORIALS TO LEARN TWILIGHT RENDER THE QUICKEST WAY POSSIBLE. See link in my signature below, or see our website.
2.READ FAQ SECTION OF THE FORUM: Light through a window...
admin wrote:How to get the sun shining through your windows:
  • Be sure all windows are only modeled with a single pane of glass.
  • Be sure you have applied a material to the glass using SketchUp's materials, such as the typical "translucent_glass_grey" or whatever
  • Be sure you use the Twilight Material Tool to click that glass material on the windows and apply the Architectural Glass>"Common" or "No Shadow" set glass material color to white and alpha to Zero.
  • Set the sun in SketchUp to cast as much light as possible into your room... the more light the better.
  • Apply material templates that are appropriate to your other objects.
  • Render a small test render with Easy01-Prelim
  • Adjust tone mapping exposure in the camera panel of the Render Window if image is too dark.
  • When happy with camera, materials, etc. Render test render at 800x600-ish on Low or Medium easy settings.
  • When happy and ready for the "final" render on Easy09 progressive. This will give you best results with so little light.
Or, the classic "tricks" of placing an invisible light emitting plane outside your window, or adding spot lights outside to cast in light... and these work fine in Twilight, but are not necessary and take some tweaking/patience.
IF PLACING A SPOT LIGHT, disable the sun, and place the spotlight some distance from the model - like about 50' or so, and aim a narrow beam of light that will completely fill the window through which you are aiming the light beam.

tuna57
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Re: Light from outside room

Post by tuna57 » Sat Jul 02, 2016 2:57 pm

Thanks Fletch. I was trying to make up for some bad info I gave Dave the other day. I think senility is setting in as I get older :shock: ! Might not have been crystal clear about the hidden wall. I'll put a wall or the ceiling in a separate group so I can hide it if I'm adjusting stuff inside the room but always turn it back on for the render.
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ntxdave
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Re: Light from outside room

Post by ntxdave » Sat Jul 02, 2016 3:49 pm

Well, I was off trying before I saw the posts from you guys. So here is what I came up with before I saw your posts.
Room v3.jpg
Room v3.jpg (165.98 KiB) Viewed 11332 times
Actually I did make the background an Emitter so I could make it look brighter through the windows.
I did change the class to Architectural Glass - Common which made it better as well.
I then added a spotlight and set the radius to 120 so it would be larger than the window and I set both of the degrees to 110 (I think).
I also made the spotlight 30000 lumens. Yes, I did not get the dramatic effect like Tuna did but I got the shadow of the lamp and chair on the wall
which is the type of effect I was hoping for. One of the challenges I see with this is being able to move the spot light so that it you can kind of emulate
different times of day. That was part of what prompted me to turn on shadows originally.

I will do some more experimenting/learning so that I can produce the type of effect that Tuna did. Chris I will go through that tutorial as that is
what I was looking for before and never did discover.

OK guys, how do I make the front wall and then get inside for the rendering? I have tried that before and was not very successful. Especially if the
room was not very big. As you can see, even after working with SketchUp for nearly 3 years (with a very narrow scope) I still have a lot to learn
that is outside the type of stuff I normally do. I want to learn all of this because I look forward to the day when I can use Twilight with the Animator
plugin. Some day, I want to be able to have a fully animated car wash that shows not only the car going through it (animated) but all of the rest of
the building (office, support equipment, payment booth, vacuum system, and etc.).

I am learning a lot from you guys and LOVE it.... :rspkt:

Chris
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Re: Light from outside room

Post by Chris » Sat Jul 02, 2016 4:24 pm

ntxdave wrote: I then added a spotlight and set the radius to 120 so it would be larger than the window and I set both of the degrees to 110 (I think).
The radius only effects how soft the shadows are. There is no need to make it as large as the window (in fact, don't! You probably won't get good results from a light that large).

110 deg. is probably too large (but that depends how close your light is to the frame). If you right click on the spot light and choose "Set Light Target", you will be able to see a preview cone drawn in the SU view that will show you how the light falls on your scene. I recommend reducing the angle until it just fits around the window opening.

Chris
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Re: Light from outside room

Post by Chris » Sat Jul 02, 2016 4:27 pm

ntxdave wrote: OK guys, how do I make the front wall and then get inside for the rendering? I have tried that before and was not very successful. Especially if the
room was not very big.
This is always a challenge. I'm constantly backing through walls and getting stuck. :roll: If your model has the flexibility, extend the room out to fit your camera.

tuna57
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Re: Light from outside room

Post by tuna57 » Sat Jul 02, 2016 4:29 pm

Dave , To get your scene set up on an average sized room like your living room widen the camera field of view. In your Sketchup toolbar click on camera > field of view. The default is 35 degrees I think. You reset F.O.V. in the measurement box, lower right corner of your window. On these interiors somewhere between 40 and 55 degrees allows me to get the scene I want without ending up on the outside of a wall. If your not tying to replicate an exact space you can always make the room a little larger to allow you to get the scene you want. One thing to watch for the wider the field of view your vertical lines start to lean, to fix that you set your scene for two point perspective instead of perspective. It just takes some experimenting and you'll get the hang of it.
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