45 Degree Shadows without Plug-ins



An architectural drafting tradition since the beginning of the École des Beaux-Arts is to cast shadows in elevation and section (if not plan as well) at 45° from upper left to lower right regardless of where the sun actually would be. It helps to give depth to 2D drawings, and, in fact, is scalable information about the third dimension (out of the paper); If an object projects 3 feet out from a surface, the shadow will fall 3 feet over and 3 feet down.

I’m aware TIG wrote a plugin and there are possibly other ways to mess with your model to achieve the results, but I settled on a simple method that doesn’t mess up my original model (either geolocation or other settings), and doesn’t need anything but native tools.

First off, what I do build’s on what I showed in this post about turning the entire building into a component, and then re-orienting it for different views: Don’t move the sun to it, move it to the sun. In order to leave my original model unscathed, I’ve created an empty template file with the sun set as best as possible to 45°. An open cube helps to demonstrate.

In my original model, I create a component from the building, and save out the component as a separate file to then import into the Shadow Space template document. (You can also just copy and paste)

Once there, either spread out the different orientations and make a scene to center on each, or, probably the better method, put each orientation on layers and use scenes to control layers and don’t even move the camera. This works well both with and without Layout as the scenes then import into Layout nicely.

Spaced out example:

Layout example - 4 elevations and a section in thumbnails:

This example file with a simplified temple is set for Boulder, CO:

Shadow space w Temple|2017.skp (567.2 KB)

P.S. I was almost going to present this at 3D Basecamp during the Hot Seat session, but the session ran long, and I chickened out and let it go. I’ve been meaning to put it here ever since, but @hank’s post on making shadows on the ceiling finally prompted me to do so. The example file even has shadows on the ceiling plan.

Some cool examples of my own

First off, kudos to you for making compelling, descriptive, and beautiful graphics part of your goals for Sketchup. Drawing (or 2d representation of 3D ideas I should say) is a language that is tasked with communicating complex concepts. Designers, engineers, and drafts-people should use every tool at their disposal to create a clear vision.

I actually have worked through, AutoCAD, VectorWorks, and Revit before getting to Sketchup and the arrival has been like coming home. Working in AutoCAD was a demoralizing and soul-crushing part of my career that was so removed from what I thought Architecture would be that I don’t know how anyone stays in the profession. No wonder the graphical quality of CAD-forward drawings left so much to be desired. Forget about shadows and depth, people don’t even use lineweight anymore!

Contrast that with the artful Beaux-Arts works that made something beautiful out of the act of communicating intent. Its a different world.

I think Sketchup helps to bring back at least a sense of that pride in one’s craft, making tools for compelling graphics withing the reach of all of us!

Secondly, I agree with your approach here. This was the basis of my question in

because I’d like to create a plugin where, regardless of where I’m looking, I can set the sun relative to the camera POV. In your case, you would set it to 45 degrees to achieve this effect. In Revit there was a similar feature where you could orient light source relative to view angle that did exactly that.

Hopefully, Trimble will unlock the vaults on this feature so the API can at least access the needed functionality under the hood with Ruby!