Looking for an extension for new / existing shadow analysis


I regularly do shadow diagrams (new vs existing) at work and find the process really daunting.

The aim is to identify the new shadows introduced by the new building after the existing structure is demolished.

these are the steps we do at work:

  1. export the shadows of the existing site to jpegs

  2. export the shadows of the new site to jpegs

  3. import the these jpegs into photoshop layers

  4. reduce the new shadow layer transprancy to 50% so the difference is in a grey colour representing the new shadows

  5. use the magic wind to select the grey areas. fill with a blue colour

repeat the steps for the other daylight hours and different seasons.

is there an extension or software to automake this process?


wow, so much effort… why don’t you set up a template of scenes with the times you are interested in… put the buildings in separate layers… take the scenes into layout and generate pdf from there… no photoshop… you are spoiling them… a new project, just replace the models in the same template.

PS… if the buildings are identical position on the page, then toggling between the pages will clearly show the shadow differences to any but the most unobservant person with all the photoshop tricks…

do this all the time in presentations

tell your client how much this gymnastics costs him or you in fees and let him tell the Australian Council ? building inspector where to go!

Better still, tell the building inspector to advance out of the middle ages and learn SketchUp…

sorry for the rant… authorities with unreasonable demands touch a raw nerve

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i like the template idea. but the new shadows need to be colored as required. i am surprised there has not been an extension for this and wonder how the architects around the world deal with this.

Tig has a plugin to make shadows into geometry that you can then colour.


yep that might be the way to go, vector geometry will be a lot easier to manipulate… and all in SU

another technique might be to export just the shadows as tiffs, vectorise them…Coreldraw or similar… and then boolean them to separate the new from old…

I assume you want to produce a hard copy publishing…I suggest you have a good hard long look at Powerpoint…yes Powerpoint… it is not only for slide shows…and is now a very capable illustration and publishing package … I have not touched MS word in years, and while wanting to use Layout always revert back to Powerpoint to get my work out… quickly…

a lot cheaper than Indesign, universally available and just as capable for 95% of everything you do…

just pay attention to your slide size and understand how master slides and layouts work, I use A3, custom size… not Microsoft A3, [20 years and they still cant get metric sizes correct). and set a 0.2cm grid .I sometimes use A1 for architectural plans… you can import svg or png files directly into PowerPoint, tint then, add transparency… hell you can even import 3d models into it now . fbx files and fly around them

Here is a link to a Powerpoint I am preparing at the moment A3 size architectural plans and signage design details to scale [**all draw natively in Powerpoint]

it is an editable pptx file so you can understand its organisation

I wish LAYOUT was so easy and universal as this… or at least LO had a import / export PPTX capability.

PS, Google Slides is also rapidly advancing its capability to a similar level too!

some sample screen capture images below from Powerpoint A3 scale drawings

Some things to note,
1] each of those lettered symbols in the plan are hotlinked to another slide that details that sign,
2] if you hover over that symbol, the sign description is displayed like a tooltip
3] As everyone has powerpoint, everyone can collaborate with the design development without data duplication… data and effort becomes persistent and cumulative, not isolated

For example, this is easily translated into other languages by those that have that skill [ they do not need specialist CAD skills or software]… Clients can edit the work for their own particular requirements

Note: I am definitely not an MS fanboy, in fact I keep a very close eye on alternatives

But I hate wasted effort and dead end data… thats way LO has frustrated me,
it needs to open up and talk easily with everyone, eg DWG , SVG, URLs,

And Powerpoint is by no means perfect, it needs

1] correct Metric implementation [typical american software issue]
2] ability to lock objects
3] deeper zoom levels [that is why my minimum slide size is A3]

Maybe I should create a new topic :slight_smile: POWERPOINT as an alternative to LAYOUT

I don’t have powerpoint, you need to have office to have powerpoint and many people don’t bother buying office these days.

Everyone but you :slight_smile:

ok almost everyone, certainly everyone I work with does :slight_smile:

PS, you have google Slides? its free and quickly reaching the same capability + its live collaboration

Daylight from MBS Software has a transient shadow option. This allows you to specify the interval for your shadows and will cast the shadow from your proposal in the color of your proposal. They have a free seven day trial you can download.

1001shadows.com (same authors as the very useful 100lbit toolbar) is a specific extension for generating site shadow analysis. I haven’t used it in a while so not sure if it is compatible with SU2020

Check out our Shadow Colour extension agileform.ca