Shadow Analysis possible with this free software?


#1

Hi,

I have a contour diagram of my land and a basic idea of the building layout I wish to have architected and built.

Before I proceed with spending I would like to enter this in a very ridumentary form and the altitude, long/lat of the location and look at the shadow affects on the land at different times and days of the year.

The purpose is to visualise the shadow impact on intended vege patches and if necessary adjust building positions to accomodate adequate growing conditions through the year.

Can the free version of the software do this?

Would you have any pointers to tutorials that will help me hit the ground running with

  • very basic contour input on top of which basic blocks for the buildings can be added
  • setting the location coordinates and altitude
  • viewing the shadow impact at different days/times

Other options I have are

  • autodesk formit - spent an hour or two and found myself spending a lot of time learning it, plus it was slow in a browser interface
  • look into options suggested to me of Sweet Home 3D and another similarly named cheap commercial package I forgot the name of right now.

Cheers.


#2

I believe it is possible with Make…I know that it can be done with SU Pro. The company propaganda from the website is pasted FYI:

"Shadow Studies-Analysis & Advanced Operations

SketchUp’s powerful, real-time Shadow Engine lets you perform accurate shade studies on your models. All you need to know to calculate the position of cast shadows is the date, the time of day, and the location of the model on the globe. SketchUp makes it easy to geo-locate your model to give it a physical location. The Shadow Settings panel does the rest. Just slide the Time and Date sliders to see cast shadows changing in real time. Use Scenes to create convincing shadow animations that you can export to videos."

Here are some url addresses that may help by showing you more info on shadow analysis:


http://kjzhang.freehostia.com/sketchup_shadow_study_tutorial.html

https://sites.google.com/site/sketchupsage/tips-tricks (Look for the section on Shadow Studies)
https://sites.google.com/site/sketchupsage/master/geo/creating-real-world-shadows
https://www.youtube.com/watch?v=EWvXiDg7AXU

You will find SketchUp much easier to learn and you will probably become productive faster than with ACAD.


#3

Thanks for that, some good resources I’m looking through now.

I notice custom coordinates includes lat/long, but not altitude, which I understand does have an impact on the calculations. Perhaps this is input somewhere else?

Also wondering about anything that demonstrates basic methods to input contours.


#4

See this thread for a discussion of the altitude question:
Astrodynamically Correct Shadows at Altitudes Much Greater than Z=0


#5

Not to worry @shadows, unless you’re growing veges on the International Space Station.
Altitude has no practical bearing on your terrestrial shade analysis.
You will not find an altitude setting in SketchUp’s geo-location or shadow dialogs.

The topic @DanRathbun referenced relates to an experiment in rendering shadows cast by a satellite in Low Earth Orbit; an altitude somewhere between 160 kilometers (99 mi) and 2,000 kilometers (1,200 mi).


#6

So being at an altidue of 1000m, which makes the earth basically 1000m greater in diameter has been proven to have an efect of only minutes at sunrise / sunset?

It does bring to my attention the surrounding mountains, which might also have an impact on sunrise/sunset time, but perhaps again a 300m high peak really only delays sunrise by 5-10 minutes?


#7

300m results in much less than 5- 10 minutes.

A mountain top 4000m above sea level leads to 7minutes and 52 seconds difference.
The 4000m top receives its sunrays at the same time if it is about 1.967 degrees “further away” from the sun on the earth’s circumpherence.

Meaning a difference of (1.967/360) x 24hours —> 7minutes and 52 seconds.


#8

NO. The earth does not swell or shrink. It’s diameter remains relatively constant.


#9

It’s not a mountain top standing above sea level by 1000m. Such a thing would see the sun that little bit earlier

It is instead a large mountainous area, whichi effectively serves as a plateau around 1000m above sea level. As the sun has to rise “over” a slightly bigger horizon, I suggested the impact is to serve as “effectively” a larger diameter earth (for this region).

Perhaps the thing to do is model the whole mountainous area, including those mountains on the horizon which serve to impact sunrise/set to get an accurate picture - is that practical? Material?


#10

Btw, with the matter aside of the mountains, this software has worked out to be a total breeze to use. A very productive use of my time compared with other efforts. A rough trial of the building layout without getting too careful about accurate details was complete in just a few hours.


#11

A model several hundred kilometers in size isn’t practical.

Frankly, I think you’re dwelling upon a rather insignificant bit of minutia and missing the big picture.
A minute or two difference in the precise moment of sunrise sunset won’t make or break the veggie crop.

However, the azimuth and inclination of the veggie plot itself will have a tremendous impact upon the solar energy the soil and plants receive.
If you live in the northern hemisphere then obviously a south facing slope would be preferable to a north facing slope.

Resources:

United States Naval Observatory — Astronomical Applications - Data Services
http://www.usno.navy.mil/USNO/astronomical-applications/data-services



#12

It’s just a question Geo. I’m asking if it makes a considerable difference in the number of direct sun time or not. I’ll take it your opinion as not.

If you live in the area, you notice the difference it makes as you entirely miss the sunset and sunrise experience in it’s amazing sea level form. But it’s not easy to time it. I figured here some people would be experts in the topic and be able to qualtative advice to help put it in perspective.


#13

[quote=“shadows, post:12, topic:11767”]… I’m asking if it makes a considerable difference in the number of direct sun time or not. …
[/quote]
The difference in time will be next to zero. Whether at sea level or at an altitude of 1000m. Taken that you refere to a location somewhere on flat terrain!

p.s.just that mountain peak (only right on top!) at an altitude of 4000m (see previous post) will have 2x ( 7 minites and 52 secons ) of extra sunlight with sunrise and sunset east->west


#14

It isn’t practical, but to a reasonable first approximation it also isn’t necessary. Treat the local earth surface as flat, and you will see that shadow length is proportional to object height and shadow direction is the same for all objects at each time. So, just scale up the length of shadow from an object in your model and you can calculate how far from the mountains their shadow will fall. Not exact, but exact probably is overkill.


#15

Thanks for sharing your experiences. I wondered the same, but havent had enough time with these type of tools to learn the ropes yet and wanted to double check. The building investment is pretty substantial for me once the shadow analysis is complete. I feel more confident in my approach with the product now.