Rendering Self-Illuminating Materials that cast light.

[Anonymous]

I have been trying to model box lights and signs for a bit now on a project we are doing renderings for, and have had no luck. For whatever reason, it seems like my self-illuminating materials do not cast any light, and instead appear only as sharp bright objects. I've attached a screen of part of the rendering (sorry, can't show the whole thing at this stage in the project). 

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I've been sticking to the default materials to try and understand the issue. The material I'm using here is the built in LED Green - On and I have also tried Lighbulb - ON. I know from other posts such as these that others have been able to execute the same process (in the third link, with the same material) with no issues. I'm rendering at interior sun+artificial but none of those settings have made a difference, nor has rendering in the cloud vs locally. 

http://www.revitforum.org/rendering-gallery/8191-backlit-signage.html

http://therevitkid.blogspot.com/2014/07/another-cloud-rendering-issue.html

http://forums.autodesk.com/t5/visualization/how-do-you-make-object-glow/td-p/3936143

(see 3rd post, link to image where LED Green works correctly)

Of course, this isn't even the most complicated sign in the project. One is neon, and I know self-illuminated materials are how I need to execute that, but they just aren't working for me. 

Any ideas on what I can do to fix this would be greatly appreciated, there are 10 something signs around the project and it would be great not to build complex lighting fixtures that still look wrong for each. Thanks!

[Anonymous]

Unfortunately I have had no luck with this issue still. I created a new family for a different sign and loaded it into a different model, and have again been unable to create a self-illuminating material that casts light on walls around it.

[Anonymous]

Self illuminating materials are exactly that, SELF ILLUMINATING. They do not cast any light at all. If you need a "glow" kind of effect you will have to create a light family and add a light source in order for it to cast light onto other objects. For a sign kind of situation it can be tricky to get to look right. I don't have any "magic bullet" types of solutions.

[Anonymous]

Thank you for your reply, but I believe this to be inaccurate. In the material preview in Revit, self-illuminating objects are shown emitting light.

Consider also the various forum and blog posts I linked above, which each show self illuminating materials casting light in Revit. Here is another : http://whatrevitwants.blogspot.com/2013/09/materials-assets-transparency-and-self.html

Unfortunately, while I can create a backlit sign fairly easily with light sources, other signs in the project are front lit, or in one case neon.

[Anonymous]

An update for anyone who was curious, at some point the self-illuminating textures started to work, when rendered through the cloud. This is curious, as I had used the cloud to produce the green image above as well. I think what happened was the luminescence was way too low in the above rendering, and when I tried to tweak it and test it, I did so locally, which stopped the effect. I am still unsure why it won't render properly off the cloud, but I have what is needed for now.

[Anonymous]

 The self-emitting light objects should look exactly like the object in the photo below. At least this is how other 3d modeling software will do: just cast the light around a self-emitting light object.(below image was rendered in rhino)

[Anonymous]

 loborocket wrote:

Self illuminating materials are exactly that, SELF ILLUMINATING. They do not cast any light at all. If you need a "glow" kind of effect you will have to create a light family and add a light source in order for it to cast light onto other objects. For a sign kind of situation it can be tricky to get to look right. I don't have any "magic bullet" types of solutions.

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loborocket you are wrong, revit is just lacks this capability

[Anonymous · Accepted solution]

It was a curious issue. I have had a lot more experience rendering in Rhino and V-ray some years before this project, which was better suited to Revit's platform.

I think the way self-illuminating materials are handled in Revit's native rendering engine vs through cloud rendering makes a huge difference. 

Of course, it's been some time and my memory is a little less perfect but I believe raising the luminance to absurd levels (something like 100000-200000 I think) made the real difference.

When I was working through the issue, I did a lot of trial and error. I think I made the mistake of making my adjustments and tests locally, to speed the process up. When I switched back to the cloud with my altered (i.e. drastically exaggerated) settings, it worked.

Attached is another screen from the same project, which was a bit more ambitious that the back-lit sign, neon. I was happy with the result. I would show more but it's a dead giveaway what the project was. 

[johnXQX4J]

Self-illuminating materials appear as a light source  well in Enscape renders