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lmcgill2
Posts: 8
Registered: ‎01-14-2011
Message 1 of 6 (1,030 Views)
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Light Level & Light Source Issue - Revit MEP 2013

1030 Views, 5 Replies
01-18-2013 04:37 AM

I'm hoping someone can give me a reality check here.  I was experiencing an odd issue yesterday and decided to test it today.  I'm laying out some lighting for a new high school project my company is working on and noticed that my exit signs and emergency lights we contributing to the lighting level in a space.  I decided I didn't want this to be the case, so I changed the fc of the two fixtures to 0.  This had no effect on the lighting level.  So, I decided to take it  a step further and changed the fixture to a non-light source.  Again, this had no effect.  To really put this issue to test, I created a brand new light fixture family from scratch.  I selected Generic Face Based family to start, created a 6"x6"x6" extrusion in the center, and changed the Family Category to Lighting Fixture (again left the "Light Source" box unchecked).  When I loaded this family into the space in question, it actually RAISED the lighting level in the space.  This is truly baffling me.  Anyone have any ideas?

*Expert Elite*
CADastrophe
Posts: 3,166
Registered: ‎08-28-2009
Message 2 of 6 (1,026 Views)

Re: Light Level & Light Source Issue - Revit MEP 2013

01-18-2013 05:33 AM in reply to: lmcgill2

I was unsuccessful in reproducing this behavior - can you try testing this in a new project and see if it still happens?

Corey D.                                                                                                                  ADSK_Logo_EE_2013.png    AutoCAD 2014 User  Revit 2014 User
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Active Member
lmcgill2
Posts: 8
Registered: ‎01-14-2011
Message 3 of 6 (978 Views)

Re: Light Level & Light Source Issue - Revit MEP 2013

01-20-2013 06:35 AM in reply to: lmcgill2

UPDATE: To really put this issue to test, I created a brand new light fixture family from scratch. I selected Generic Face Based family to start, created a 6"x6"x6" extrusion in the center, and changed the Family Category to Lighting Fixture (left the "Light Source" box unchecked). When I loaded this family into the space in question, it actually RAISED the lighting level in the space. This is truly baffling me. Anyone have any ideas? Note, this was all done within the same project as before, so I suppose I need to create a new project and try this out.

 

I'll get back to you.  THanks,

Active Member
lmcgill2
Posts: 8
Registered: ‎01-14-2011
Message 4 of 6 (963 Views)

Re: Light Level & Light Source Issue - Revit MEP 2013

01-21-2013 04:30 AM in reply to: lmcgill2

UPDATE #2: 

Ok, this time I took it a step further.  First I created a simple room to link into my test project.  I simply created a 10'x10' room with a floor and a ceiling.  I then created a second project with Revit's out of the box "Electrical Template".  I linked in the previously mentioned "Room".  Made the link "Room Bounding" and created a space inside that room.  I placed two of Revit's out of the box 2x4 Plain Recessed Lighting Fixture.  I selected the space and recorded the "Average Estimated Illumination" value of 75.29 footcandles.  Next is where things get odd again.  I then created a dummy light fixture that is NOT a "light source" (that is, I left the "Light Source" checkbox UNchecked).  Again, this is simply a 6"x6"x6" extrusion classified as a "Light Fixture".  When I placed one of these "Fixtures" in my space the Illumination jumps to 120.10 fc.  If I add more to the space, the illumination stays at 120.10.  Very Odd.  I've zipped the Linked Room, the Lighting Project where I take my measurements, and the light fixture family if you'd like to take a look, but it seems the files are too large.  If you'd like to see them I would email them to you.  Note, I did not see this behavior in Revit MEP 2012.  Just in 2013.  Thanks,

Active Member
lmcgill2
Posts: 8
Registered: ‎01-14-2011
Message 5 of 6 (921 Views)

Re: Light Level & Light Source Issue - Revit MEP 2013

01-23-2013 04:33 AM in reply to: lmcgill2

For anyone who is following this topic, I've found the solution from another thread.  See explanation below from poster:

 

"Let me guess... if you put the 6x6x6 fixture at or above the elevation as the 2x4 fixtures, the Average Estimated Illumination (AEI) value on the space doesn't change... however, the lower you put the 6x6x6 fixture, the higher illumination level you get.

In 2013 we changed how the AEI is computed. In prior releases, we received feedback that users had difficulty validating the AEI value... especially when lighting fixtures were at non-uniform elevations, or had geometry/hosting that made it unclear as to what Revit used as the elevation of the fixture... so, we simplified things, and introduced the 'Lighting Calculation Luminaire Plane' (LCLP) parameter on spaces to make it clear. The LCLP value is is determined based on the lowest Lighting Fixture in the space. So, as you check your AEI values, also keep an eye on what the LCLP value is, and confirm that this explains what you are seeing.

In this case, it would probably make sense when determining the LCLP to omit fixtures without the 'Light Source' family parameter set. We'll log it for future consideration"

 


Sooo, unfortunately, even fixture with no "light source" will lower this LCLP and cause the AEI to increase.  To me, this makes any illumination estimation tools within Revit useless.  Hust my two cents.  Thanks for all of your help, regradless.

 

 

*Expert Elite*
CADastrophe
Posts: 3,166
Registered: ‎08-28-2009
Message 6 of 6 (916 Views)

Re: Light Level & Light Source Issue - Revit MEP 2013

01-23-2013 05:36 AM in reply to: lmcgill2

Confirmed.


"... so, we simplified things..." 


Never seems to be a good thing to hear...

 

Anyway, thank you for posting this information here!

Corey D.                                                                                                                  ADSK_Logo_EE_2013.png    AutoCAD 2014 User  Revit 2014 User
──────────────────────────────────────────────────────────────────────
⁞|⁞ Please use Mark Solutions!.Accept as Solution and Give Kudos!Give Kudos as appropriate to further enhance these forums. Thank you!

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