Shadow and Nightfall

Hi,

I am using a current view from Grande Prairie (GP), Alberta, Canada. In it I am constructing an 8-storey structure to see what kind of shadows it creates. As I slide the month slider to June/July, and time slider over to around 8pm, the base map goes quite dark. In GP, there is quite a bit of sunlight (past 11pm) in the summer months because of its latitude. Why is would my base map be going dark from around 8pm to the morning hours? Is it a perception issue on my part, or is it that the shadow feature is for more common (New York, Toronto, etc) latitudes?

Thanks!

Hi Brad and Jane,

Have you tried changing your location?

Go into Window>Model info>(select)location>and adjust to the closest location to where you are (choose country then location).

Hope this helps,

ethip

Hello Brad and Jane ... My fellow Canadians.

Have you input the correct Long/Lat coordinates in SU ?

Have you adjusted your Shadow Settings in which you can adjust the Light and Darkness slider settings ?

Have you selected the "Use Sun for Shading" option ?

BTW- Are you using i.e. have you imported, a Google Earth Terrain/ Image that has the Geo-Reference information ?

The latter is not necessary providing you have input the correct coordinates in SketchUp.

Answers to these question may in fact resolve your issue. Alternately, it they will provide information that may be useful to mmyself and others, to be able to affectively assist you.

Eh ?

Hi Brad & Jane,

I would avoid using an imported GE view as the basis for an accurate shadow study.

The SU User’s Guide contains the following warning:

>Caution - Do not use the Location panel in the Model Info dialog box to change the location of a model after importing the current view from Google Earth (using the Google Plugin). Using the Location panel to position models in Google Earth will likely result in an incorrectly located model.<

Accurate shadow studies require precise input of geographic location and solar orientation of the model.

Use the Window > Model Info > Location > Set Custom Location dialog box to accurately input your model location.

Use the Solar Orientation > North Angle box to set TRUE North (Not Magnetic North) in relation to the model. To access the dialog window easily, click the Georeferencing Icon in the Status Bar at the extreme bottom left of the screen.

The SU User’s Guide also contains the following:

>Because some time zones lines zigzag rather dramatically, the time zone for some locations may be inaccurate by up to one hour (sometimes longer).<

Be aware the Time indicated in the SU Shadows control panel is Standard Time only. There is no automatic provision to adjust for

Daylight Saving Time. Also, take into consideration the close proximity of Grande Prairie to the time zone border, which may skew

your perception of accurate shadow timing.

To obtain proper Time/Shadow relationship, you may need to adjust the Time Zone in the Set Custom Location dialog box to correct for these variables.

To verify your settings, accurate sunrise/sunset information for your exact location is easily available from the US Naval Observatory website at the link below:

http://aa.usno.navy.mil/data/

Information regarding the difference between True North and Magnetic North is available at the link below. The difference in the Grand Prairie area is considerable. (>18 deg.)

http://www.ngdc.noaa.gov/geomagmodels/struts/calcDeclination;jsessionid=00A94F3B69155DDE7B0E576CA86075CE

Details about the application of Magnetic/True corrections are in the thread links below.

Pro 7 sun orientation

North Question Redux

Best regards,

Geo

PS

RE: SnowTiger … Fellow Canadians.

I’m not Canadian, but I feel a special bond with them. Before the US entered WWII, my father volunteered as a cobelligerent to serve in the Canadian Army, already involved in the war. He served 4-1/2 years in North Africa and Europe with the Quebec Three Rivers Armored Regiment as Gunner/Loader in the Sherman M4A4 and Firefly. Our family continues to keep in touch with the Alberta family of the only other member of the original 5-man tank crew to survive the war. Two brave boys, barely 21 years old at the time, both gone now.

Thank you everyone! I will try these suggestions (sequentially) when I get a chance tonight!

Geo,

Apart from your comprehensive answer (which I'll rate 5 stars) I would like to rate the PS a 10 stars. Thanks for sharing!

Truly a father to be proud of!

Wo3Dan

Here here!

Hi Geo

Your father is worthy of our pride as well as your's. We continue to honor his memory along with the memories of many

others. Thank you for sharing some of your family's interesting heritage.