Walking and Relative to View

When we turn on shadows in a camera view they are affected by a subtle setting called Relative to View.

This setting is part of the Sun Settings dialog. When we turn on shadows in the view, activate the Steering Wheel and use the Walk feature the shadows will move as we walk when Relative to View is checked.

This caught me off guard today while discussing it (the Walk feature). One of the guys noticed the shadows were moving and remarked, "Why are the shadows moving? That can't happen as you walk through a building or around it!"

I wasn't focused on it, didn't even notice it... It took me a moment to get out of my fog, and in that moment, I even imagined Walk was moving the building instead of the camera (walking to and from the building). Then I opened the Sun Settings dialog to check things and another person said, "Oh it's got to be that!" (Relative to View). Yep...

When the option is not checked the shadows stay fixed relative to where the Sun is located. Crisis averted :)

New Revit Family - Solar Light Bulb

Okay, we need a Revit family for this guy's unique solution to lighting!

[Added 3/25/2012] Decided to add the video that Alfredo mentioned in his comment, thanks!

Dept. of Quirky - Baluster with Light Fixture

A thread at AUGI has been documenting the design process for the lair (currently called Project Sauron) of an as yet undetermined alleged evil Lord and Master (LaM). One of his designer minions (Mortimer, who also apparently uses Revit to do his work) has been posting images and asking questions. He recently asked about creating balusters that incorporate a light source. Since this minion has demonstrated pretty savvy skill with Revit already I suspected it was a loaded question, as in he has his answer but curious if anyone else has noticed. I guess whenever an evil Lord and Master is involved I get a little suspicious?

My first thought was a nested light fixture would need to be used and that it would need to be "shared". I thought shared because we have to nest multiple fixtures in a chandelier to create multiple lamp light sources...and they need to be shared for them to render. At least that's how I remember it. Turns out using a "shared" nested light fixture has a pretty weird outcome when used in a baluster and applied to a railing.

See the light off to the left of the railing? That's the nested shared light fixture family. It's locked and aligned to the side of a baluster yet only one light fixture shows up and a little farther away from the baluster than I expected it to be. That and there's only ONE, despite the number of baluster you can plainly see. Even stranger is that I can select the fixture and move it independently from the railing. I can move it next to the railing, but there is still only one.

This time I made a couple changes. I removed the "shared" status of the light fixture and reloaded/rebuilt it all because Revit hates switching between shared and not shared status. The result is a bit more like what I expected this time.

Even better, it renders each fixture!

I hope the LaM treats his minion well after sorting this out?

Unfortunately the videos this post also had embedded have since become unavailable so I've removed the dead links.

Lighting Calculations by AGI for Revit

The folks (Lighting Analysts Inc.) that create AGI32 (a popular lighting analysis tool for AutoCAD) are in the Beta process for their new application for Revit called ElumTools.

From their website:
...snip
ElumTools is a calculation Add-in used to predict the performance of electric lighting systems within the Autodesk® Revit® Architecture or MEP software. With ElumTools the need to utilize external software to compute illuminance from light sources placed in Revit is no longer necessary.
...snip

Click HERE if you'd like to join their BETA Process. The pricing structure has not been defined yet, just TBD on their site.

Want to watch some videos?
ElumTools Test Drive
ElumTools Overview
ElumTools Visualization

To get you started I've embedded the Overview Video.

Revit MEP - Light Levels

Jason Combs a P.E. (Professional Engineer) with Woolpert, Inc. was worried about me. He noticed that I hadn't posted in a couple days and sent me this so I could keep on track. Okay, okay I may have stretched the truth a bit. He wasn't worried about me but he did share this information with me the other day and it seemed so nicely put together that I might as well just put it here too. He said it was okay so here it is!

Jason writes:

Adjusting the elevation of a light inside of a space will change the lighting level in the room. Following is a significant set of characteristics affecting the way lights work in a room/space.

Light families must have a light source to add illumination to a room. In other words, in order to schedule the estimated illumination of a light, a light source must be added to the family through the Categories and Setting dialog within the family.


The illumination in a space is related to a light family's Illuminance. But don't be confused when scheduling Illuminance versus Illumination. Following are two schedules, one is a Light Fixture schedule and one is a Space Schedule with Lighting fields included. Illuminance of a light is based on a given foot-candles amount at a given height (i.e. 10fc @ 10'). Illumination in a space is dependent upon the number of lights and at what level the measurement is taken for a given set of light Illuminances.


The Light Source location is what matters when it comes to measuring the illumination in a space. The following image depicts that the light source is within the space. However, there is an unclear limit to where the light source must exist within a space. After some testing, I (Jason) determined that the light source must be within 1'-0" of the space and exist on the same side of the work plane to included in the space. Further I (Jason) was able to adjust the tilt angle of the light source from -90 deg to 0 degrees and still existing within the space.


Without the Light Source visible it would appear that this standard troffer light in the following image is outside the space. But no, Revit still considers it to be within the space because the light source is within 1'-0" of the space even though the visible geometry is entirely outside. Just remember to keep the light source within the space!


Here's an example illustrating that the Light Source location affects lighting calculations. Flipping the work plane of the light can significantly change the illumination value in a space.


In the following example it appears that Adjusting the Tilt Angle of the Light Source did not change the illumination calculation within the space.

Thanks for sharing this Jason!

Visa Lighting & Revit Content

Visa Lighting has created Revit lighting families. They feature a screen shot of Revit on their website and there are Revit families for each of their products. Be sure to check them out and let them know if you like them.