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Sun brightness accuracy?



How accurate is the sun brightness? When I bring a model in from Sketchup, does Shapespark know the time of day, month and year of the Sun being brought in?

I ask because I am modeling a house that looks fairly dark (I haven’t added light).





When you choose the Include Sun option in the SketchUp export dialog, only the sun position is exported. The strength of the sun will be at the default value and you need to adjust it.

Have you lowered the opacity of the windowpanes close to 0 to let as much as possible of the natural light inside?


Hi Wojtek,

Is the default value accurate though? I can turn up the strength of the default value but then the room looks brighter than it will be in reality.

I haven’t lowered the opacity of the windowpanes. That is the same as my above question though, if I lower the opacity, am I cheating? I want the most accurate light levels, if the room is too dark I want the architect to know that.


Currently Shapespark isn’t meant for illuminance analysis, mainly because it doesn’t offer the feature to measure the illuminance in lux unit, and because its sky and sun model might be too simplistic for this goal.

So, for architectural decisions regarding lighting it’d be better to use another tool like DIALux.


Okay Wojtek thanks for that

How accurate do you think the lighting is in Shapespark? I know it doesn’t calculate lux levels but does it give a fairly accurate representation of actual lighting?


Hi John,

Rendering a scene in Shapespark is like taking a photograph: The result depends not only on the objective scene illumination (measured in lux units), but also on how you set the camera. You can make a bright picture of a dark scene and a dark picture of a bright scene. And as with a camera the usual goal of using Shapespark is producing a “good-looking” picture on a medium which has narrow dynamic range when compared to the human eye.

To have an objective measure of how bright/dark the interior is you would have to use lux unit, because such values could be easily compared against norms and recommendations.

I’d say the lighting in Shapespark is accurate but in relative terms - you can compare two interiors in the same lighting conditions to find out which one is brighter, and roughly how much brighter. However, Shapespark doesn’t have features (mainly lux measurement) that would give you accurate information in the absolute sense: “will this room be bright enough for the intended purpose?”

BTW, when comparing the brightness of interiors in Shapespark it’s best to turn off the tonemapping. There is no such a switch in the UI, but it can be done by using the below colormap in the “Camera” tab of the editor.