IES photometric Web

[Yorx57]

I have a light fixture family that I am working on, with the correct IES files to associate with the fixtures.  The problem I'm having is that the IES photometric web is ALWAYS scaling itself to a certain size (haven't found out what that exact size is).  So, on all my fixtures now, the photometric web is way to small for the fixture, and as it always seems to scale to a predetermined size, my larger fixtures are completly out of wack!

Does anybody know how to size the photometric web to it's correct size in relation to the fixture?

[maciejwypych]

Hi,

From what I understand about IES files, it's an accurate representation of a particular type of light, which means you can't really scale it, and you'd need a different IES file for a different fitting size or shape.

[Yorx57]

Hi maciejwypych,

Thnx for the reply!! I have a pretty good understanding of what the IES file is and represents, and yes technically the size *shouldn't* matter.  However, because Revit is not visually displaying the photometric web in proportion to the fixture size it's causing huge rendering issues.  My larger fixtures for example (which are all rectangular and hang off of the ceiling), which do have their proper respective IES files attached are rendering with the photometric web taken literally - meaning a huge bright spot in the center and the ends not being lit up at all - and you can literally "see" the photometric web shape. Also, Revit is using the IES in conjuction with the material settings as far as how much light is being outputted based on transparency/translucency settings. So, with the material settings set to display what would appear to be correct along with the IES file and photometric web, the rendered output is just absolutely horrible and completely unusable.

Are people only using IES files for recessed fixtures where the fixture itself is not visible?

[vanessa.hall]

Hi Yorkx57,

I understand you are working with a light fixture family where the IES photometric web continues scaling itself to an undesirable size. 

Instead of controlling just the IES file, have you tried to set up different types in the nested family with the different IES files?  You can then control the type of nested family in the host family which may eliminate the scaling issue.

Please let me know if this resolves your issue.

Best regards,

Vanessa Hall
Autodesk Support Team

[Yorx57]

Hi Vanessa!

Thank you for helping me out with this! My current setup is 2 family types (eventually it will be 4) in a ceiling hosted light fixture template.

Each family type has it's own proper IES file associated with it. I have the light source emit from shape set to rectangle and sized to the fixture - however, I did have to throw my emit shape out by 90° on purpose (switch my length and width values) to get it to render properly (an issue that has been around from at least 2012 and still hasn't been fixed). I have attached 3 image files that hopefully will better explain what I'm having problems with.  The small.png and large.png files show the Rivet family editor with the respective fixtures (the small one and the larger one) overlayed with AGi32 reading the same IES files and how it is correctly *visually* displaying the web in relation to the fixture.  The third file is just a quick and dirty rendering to see how the IES files are working.  It's a small room with the 2 fixtures hanging.  Material is set to 40% transperency and 100% translucency, rendered at medium with artificial lighting only.  As I mentioned in my previous post the issues is that Revit is "seeing" that web lilterally, but because it's not sizing it correctley to the fixture, it's completly throwing the rendering out to lunch (extremely noticable in the larger fixture)

[vanessa.hall]

Hi Yorx57,

I;d like to confirm a few details to ensure we eliminate some culprits for this issue.

First, Are you using a manufactuer's IES file?

Also, in order to specify the Photometric Web, are you utilizing the following menu options?

• Open the lighting fixture family in the Family Editor.
• In the drawing area, select the light source.
• Click Modify | Light Source tabLighting panel (Light Source Definition).
• In the Light Source Definition dialog, for Emit from Shape, select the desired shape.
• For Light distribution, select  (Photometric Web).
• Click OK.
• Save changes to the lighting fixture family.

And lastly for the IES file selection as it pertains to the family adjustments...

Are you having the IES file define light distribution for the entire lighting family OR selected instances of the light fixture family?  

I ask because there are separate areas to specify these properties.

[Yorx57]

Hi vanessa,

---

@vanessa.hall wrote:

Hi Yorx57,

I;d like to confirm a few details to ensure we eliminate some culprits for this issue.

First, Are you using a manufactuer's IES file?

>No.  We ARE the manufacturer and create our own IES files with Photopia. I am also aware of the problem with Absolute photometry in Revit, all of our IES files are produced with Relative testing.  However, I have tried other IES files for some of our fixtures that have been physically tested simply for testing purposes and get the same results - the web will always scale either up or down to a specific, pre-determined Revit size.

Also, in order to specify the Photometric Web, are you utilizing the following menu options?

• Open the lighting fixture family in the Family Editor. 
• In the drawing area, select the light source.
• Click Modify | Light Source tabLighting panel (Light Source Definition).
• In the Light Source Definition dialog, for Emit from Shape, select the desired shape. 
• For Light distribution, select  (Photometric Web).
• Click OK.
• Save changes to the lighting fixture family.

Yes, and as noted earlier, the Rectangle emit shape was selected (have also tried point, again just for testing purposes)

And lastly for the IES file selection as it pertains to the family adjustments...

Are you having the IES file define light distribution for the entire lighting family OR selected instances of the light fixture family?  

I ask because there are separate areas to specify these properties.

Sorry, I am very new at Revit and so I hope I understand this question correctly.

I believe you are asking me if the "Photometric Web File" parameter is set as a family or an instance?  It is set at it's default, a family.  Each type has it's own proper IES file selected for the "Photometric Web File" parameter.

Thanks again for all the help!!

---

[vanessa.hall]

Hi Yorx57!

I've done some additional research which is all leading back to the IES file itself.  There is a known issue stemming from an IES file is using "absolute" value photometrics. For some reason this causes hiccups within Revit for unknown reasons.  The suggested fix is done by assigning a "-1" value to disable the "absolute" value.

Please let me know if this fix resolves your issue when you have a moment.

[Yorx57]

Hi Vannessa,

Thanks again for looking into this for me. 

Just to clarify, as stated in my previous post, I am aware of the "absolute" bug - all of our fixtures (when software generated) are done in "relative" mode.  Also, I'm slightly confused by your response in that assigning a "-1" should set the IES file as "absolute" (as there is no lumens per lamp that can be tested), any other value should set it as "relative" (the lamp has been tested independently and therefore a value can be assigned).

I have tried the IES file with the -1 value and still am getting the exact same results in the family editor and a nice colour spectrum when rendering (the bug)

Also, I have attached both IES files. They are the exact same other than one has been set to absolute.

[vanessa.hall]

Good Morning!

I've gone back through our chain and sought some additional guidance about the lighting problem. The IES files are your own so those would be built to your specifications accurately. If possible, can you send me the family files being used so we can try to see the same behavior?  

[Yorx57]

Hi Vanessa,

I've attached a zip file containing the family and both IES files as requested.

Thanks again for looking into this!! 

[vanessa.hall]

Hi There!

We have gone through the sample file given, but found it to render correctly. I've attached a picture for confirmation. We would need a sample file that renders differently in order to replicate the problem you have experienced.

Please let me know if you can provide such a file for us to use.

[Yorx57]

Hi Vanessa,

Sorry for the late reply, we were on shutdown last week.

Is it possible to get what material and material settings you had used for that?? I would like to re-run the rendering here.

Thank You.