distant light question

[Spacer]

hi,

 

i want to have my buidling in Kassel, Germany.

 

when i screen capture google maps of the building, I obtain a plan that I import into FZ; I then measure the angle of the building relative to a horizontal line and obtain 46,98 degrees.

 

I will be making Maxwell rendering for this project, but I also want to make studies using Formz.(Pro 8.5)

 

My concern is obtaining accurate sun lighting given location, building orientation and precise time and date.

 

So ideally I can make Open GL quick renders which cast the correct shadow, then obtain the same exact shadows in Maxwell.

Here are my two lights:

 

 

questions:

1. can you tell me if I have entered the long/lat data correctly?
2. in the distant light, I don't know what number to enter in the "Time Zone" feild.
3. does "Angle of site North" in Distant Light perform the same function as "Sky rotation" in the Physical sky light?
4. In Physical sky is the GMT equal to "2" for Kassel, Germany?(ok, I found it on internet but want to be sure)
5. finally, once I get the right numbers for these two lights, will the map the same shadows in OpenGL/Maxwell, or do I need to make Renderzone renders to match Maxwell?

thanks a lot!

 

Peter

 

 

[Tech]

Hi Spacer,

 

Your Angle of Site North is currently set to 90 degrees, and with the default Angle Options, 0 is at 3:00 (+X), so North would be straight up / 12:00 / +Y.

 

If you have rotated your model by 46.9 degrees, you should also adjust your Angle of Site North by that amount (either adding or subtracting it from 90, depending on which direction you rotated the model (if you did).

[pylon]

Speaking for Maxwell:

 

For Maxwell & matching shadows in openGL, you don't need to set up a Distant light. Just set up the Physical Sky and it will display sun shadows properly in Shaded Full.

 

I usually use this service for GMT/UTC offsets because it also notes Daylight Saving rules for the local jurisdiction. The offset will vary depending on whether Daylight Saving is currently enforced. Enter this value in Physical Sky's "GMT" field. (Note that the formZ Distant light has a "Time Zone" parameter, but this is not expressed as a GMT/UTC offset.)

 

[Spacer]

thanks tech,

 

Pylon, my physical sky doesn't cast any shadows in shaded work. i can't see why though..

 

any ideas? thanks,

 

Peter

 

[pylon]

Hi Spacer,

Sorry, my mistake; no lights cast shadows in Shaded Work. They do in Shaded Full, though. I have edited my response above.

[Spacer]

Hi, So I am now reposting the setting.

 

Just to be sure, Plyon: If I use no sky rotation, then my north is pointing up in Plan view, correct? Which means I need to rotate my building according to it's positioning in reality (the building exists..). this is what this SC shows:

 

 

Thanks,

 

Peter

 

[pylon]

If the "Site Rotation"parameter  is set to 0, then site north will be the y+ axis (top of page, when in plan).

 

You can model your building along the orthographic axes; just adjust "Site Rotation"parameter. It's pretty strait-forward, but to make sure you've entered the correct signed angle (+/-), perform a "sanity check" by setting it to noon on the winter solstice (December 22). Go to plan view, and make sure the shadows are pointing (approximately) site north.

[Spacer]

thanks for the "sanity check" Pylon, it's exactly what I needed...

[pylon]

This may be helpful for others who've just found this thread:

 

As of Maxwell for formZ 3.2.1.5, it is also possible to set the Physical Sky or Sky Dome sun to follow a formZ Distant light exactly.

 

In the Physical Sky or Sky Dome's Location tab, select "Follow Distant Light" from the pulldown menu, then click on the disclosure triangle to choose the light to follow.

[Tech]

Thanks Pylon!