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kikic

Making Night Lights in Windows

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Hello, i want to learn how to make building lights at night. I have been trying to search for tutorials on this. I was able to find one using a texture and projections. it worked great,  but it seemed to work on a building without windows already on it. If I am using an OBJ of a building with windows already on it, is there a way to  get the size/shape of those windows lit? a technique for making your own map?  I know this is probably a really basic question,  but I have a large gap in this sort of knowledge and need direction to  any tutorials about it. Thanks in advance!!

Edited by Cerbera
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  • yes the picture you show is exactly what i want to do. but i guess i dont know what to look for in the obj to see if it is possible. i attached my WIP, i used some free models from around and if you see the building on the left edge, it has a balcony with a window shape. i would love to figure out a way to light those windows  but i dont know if that is possible, or let's say how to make the right choice before hand with a better building for this purpose. any tips or referrals to tuts would be great. thanks!!

    Night city rndr.png

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    You have two choices, either like in my image use actual lights inside the object with a transparent material on the windows or use polygons to emit light which looks like what you have done on other buildings. If you download my model maybe it will give you some ideas.

     

    Dan

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  • Thank you, I will check it out! :)

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    My recommendation....use global illumination.

     

    Assume the base texture has the lights as stated.  That is, it is a picture of a building at night with the room lights.

     

    1) Put that texture into the luminance channel.  Now I also mask out the individual windows and use a Fusion layer with that mask in the luminance channel to insure that ONLY the lighted portions are showing luminance, but that is up to you.

    2) Do NOT put that texture into the color channel.  In fact, uncheck the color channel.

    3) In the reflectance channel, add a reflectance layer and select (my personal favorite) CGX.

    4) Under layer Color, add the texture with Mix Mode set to Multiply.

    5) Under Illumination, select GI Area Light and set strength to a very high value (greater than 1000).

    6) Select Global Illumination under the render settings.

     

    Now, of course you will have to play with these settings to meet the desired look.  For example, in the image below I set the illumination strength to 10,000.  The trick here is that if you put the base texture in the reflectance channel as opposed to the color channel, then Global Illumination renders much faster.  This test image took only 2 seconds on my computer (granted it is a simple cube with one texture, but still.....) but it gives the effect of internal lighting without the needs for placing actual lights in the scene (there are no lights used in the image below).

     

     

    Capture.thumb.JPG.d93d18e78807a034c7addf90525a03f9.JPG

     

    Note that with GI, the base texture lights up the sides of the building which really sells the effect of real lights coming out the building windows.

     

    I hope this helps,

     

    Dave

     

    And the base scene file is below (with textures and mask):

     

    Example night light.c4d

     

    And the textures

     

    towerface002a_alt.thumb.jpg.749facc9ceb846494e112b94df25b8d8.jpg

     

    towerface002a_ALT_mask.thumb.jpg.97cf5db3a7c7ac8815df5a1f8bb9947b.jpg

     

    towerface002a_alt_bmp.thumb.jpg.396ef9f2d5cb9c29a001af40bb6b9a21.jpg

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