Forums >> Revit Building >> Technical Support >> Light Fixture / Light Source - Wont Render with size change

yoyomendez

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Working on a rectangular light fixture that is parametric, so that I can adjust the size to match the ceilings it will backlight.  

The problem I run into is.......regardless of what size I make the fixture, the rendered light is always the same size. Initially I size the rectangular fixture to 8'x8'.  Then rendered the image as shown.

Then I changed the fixture size to be 20'x20', but the rendered image is exactly the same.

My ultimate goal is to backlight a fabric type ceiling, so the visible face puts off a soft glow.  I have achieved this look with multiple strip fixtures (32 to be exact), but would like one larger, rectangular fixture to replace the 32 strip fixtures.

How can I get the larger, rectangular, light source to change size with the actual fixture geometry?

Thanks in advance

Edited on: Fri, Feb 10, 2012 at 11:50:48 AM

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yoyomendez

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3d shot of the ceiling above with all the strip fixtures

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yoyomendez

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rectangular light fixture - parametric

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WWHub

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Within revit light families there can be two different light sources.  One is a spot, the other is linear.  The linear is represented by a line.  No matter how you change the box around this line, it will always be the length it was set to .... unless you make it change.

Try again....

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yoyomendez

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Ok, maybe that's where I need some help.  How do I actually change the light source to reflect the size I want?

I have attached a screen shot of the properties window for the actual light source.  Under the "Photometrics" section, emit from rectangle width, and emit from rectangle length are the parameters I have been using to change the size of the light source.

Thanks again for the help!

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aspect

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Maybe the easiest way is just to create multiple versions of the fixture, where each increase in size you duplicate the light source element within the object?

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WWHub

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Please start by reading your HELP:

Parameters for Lighting Fixtures and Light Sources

The length of the line that represents the light source in a rendered image. This parameter is available when the Emit from Shape setting is Line. (See Defining the Geometry of a Light Source.)

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yoyomendez

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So essentially you can only change the length of a linear light source, but not the actual geometry of the width.  Thanks I appreciate the help!

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jlights

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If you define your light source as a rectangle rather than a line, you can associate the length and width parameters of the light source to the corresponding dimensions of the family (or make them a little smaller if you want the bounds of the light source to be inside the body of the fixture). Also, in the light source definition, choose Photometric Web. Then in the family parameters under Photometrics, click in the Photometric Web file field and navigate to an appropriate photometric file which you should already have on your computer. There are a number of generic IES files that come with Revit. Or maybe the manufacturer has the exact phohtometric file on their website.

In the family, under Initial Intensity, choose Luminous Flux and be sure to multiply the lumen value for your basic fixture by the dimension factor used to create the length of the fixture. For example, if your basic 4' fixture has 3000 lumens and you are making one big 24' fixture, multiply the lumen value by 6 so that you don't end up spreading 4' worth of light over 24' of length.

You can also set the initial color of the light to give a warmer or cooler appearance, depending on how you want it to look. A higher Kelvin temperature (around 4000k) will give a cooler, bluer appearance, while a lower temperature (3200 k) will approximate the look of incandescent light.

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yoyomendez

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Great info, I appreciate the help!  I'll give it a shot and report back.

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SujayThomas

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Well? I have the same problem. Whether I use a photometric web or a line or a rectangle, the light merely concentrates at the centre. I edited the emit length (and in case of a rectangular light source, the width as well), to no avail. Attached a low quality render to show the issue. The light is supposed to be a wall wash - downward. There are other forums that go blank on this too.

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Typhoon

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Change the "Light Source Defenition" of that light

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isabelacastilho

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Pleeeease tell me how you managed to get that light in the first image. 

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