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gtodohoo

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Reply with quote  #1 
Hello everyone, I got the same problem as other people do when I tried to create a spot light. then I had light bleeding, and I don't know how to control it.

I believe it was Zem and there is another person gave a tutorial for that, putting an omni light inside a tube or an enclosed environment then the light would have a nice scallop over the wall, I follow the same thing, but the light went through the tube. is the sketchup version making the difference? I downloaded someone's skp files, people who can make the effect all using  sketchup 5. I really need to figure it out soon, please please give me some help. Thanks!!!
bigstick

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Reply with quote  #2 
Okay, the main thing to remember, is that if you want a scalloped effect, you have to place an omni so that its centre point is behind the 'lip' of the fitting. This is what produces the scalloped effect.

With small spotlights, smaller than around 150mmm diameter, you can't really get a realistic effect at the moment, because the minimum strength of an omni is just too powerful. For a recessed ceiling-mounted light, it should be okay, because the light bleeding should be some way above the ceiling plane, and you can create the effect.

The thing to remember is that for small lights, the shape of the omni group makes no difference. The smaller your group the better. I think you need a face with a colour to give the light a colour though. I haven't tried assigning a colour to just lines but it may work. Increasing the size of the omni group magnifies the light strength, so with small fittings having a large omni group is counter-productive.

If all this doesn't make much sense, post the fitting and I'll try and have a look either tonight or tomorrow.

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gtodohoo

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Reply with quote  #3 
thanks for the reply, here is the file which shows the problem i have. I am trying to make a spot light can cast light on wall, and on ground. thank you so much.

JChapinCP

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Reply with quote  #4 
I have a model which is looking like it will create a nice scallop. it is rendering currently and I will post it shortly. I was able to use multiple omni lights from a single line grouped into an omni object.

Does this provide the lighting effect you are looking for?


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bigstick

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Reply with quote  #5 
Try this. JChapin's approach is nice, but it will hit your render time as it relies on 4 (well it looks like 4) omnis for a single fitting.

This looks a little like a bigger version of a Louis Poulsen Ballerup fitting (http://www.louispoulsen.com). If you look at their website, in the surface and semi-recessed section you will see thid fitting and some images. You should find also that the light distribution looks a bit like my image below. I have re-sized the omni, moved it and reduced the power slightly.


You can use JChapin's recommendation in conjunction with this if you wish, but it will take a little tweaking to get right and will render  lot more slowly.



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JChapinCP

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Reply with quote  #6 
You are correct, the multiple omnis and a LEM in each fixture will increase render time. My experiment by no means is complete More than anything it was trying out the concept of combining omni lights at different distances and strengths to achieve a more even fall off.



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gtodohoo

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Reply with quote  #7 
jchapin's rendering is more close to the effect that i want. however, one problem is, the light you are using is setting up to 30 or maybe 40 feet high in the ceiling, when i made the similar light, but scale down to 10 feet ceiling high, the light start bleeding again, even i tried to reduce the light to 1, still is too strong for that scale.
JChapinCP

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Reply with quote  #8 
I dont recall changing the scale of the model...however my sketchup interface is set to feet and inches...I wonder if that did it (assuming you'd be in cm) or something else something random I did...I'll take a look at my settings. thanks for the heads up on that.

Edit:
I  quickly scaled down the model to a 10' ceiling and then had to adjust the intensity of the omnis. Here is an updated sketchup screen capture, model, and rendering. I'm at work so I cant devote much more time to this now. I am still getting a bit of bleed onto the ceiling though I dont know which omni light is doing it. Depending on your skills in post processing and the ceiling conditions you might be able to fix this as one  would in the darkroom with dodge and burn techniques.

It might take a bit of fiddling around with the the scale, distance, and intensity of each omni light to get the right effect.

but as I mentioned above this may not be the best way of obtaining this effect.


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bigstick

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Reply with quote  #9 
I didn't change your model scale, just the units. It should have been fine as it was, you only needed to change the units back. Whicheer solution you choose to adopt is up to you and I guess will depend on how much time you have for rendering

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gtodohoo

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Reply with quote  #10 
i think you guys have seen zem's tutorials, the last two images are basically what i want, i followed what he said, a tube, group light inside, but i doesn't look the same as the image shows, anyone has clue?
here is the thread
http://www.websitetoolbox.com/tool/post/supodiumforum/vpost?id=1682792

gtodohoo

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Reply with quote  #11 
jchapin, thanks for your time. appreciate it alot!
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