Shadows seems to be weird

Does anyone have the experience that the shadows are not really in line with the aerial photo?

So, for a city in The Netherlands, the aerial orthophoto has been flown on November 23-24, 2020. Image with only the shadows that can be seen in the aerial image: 101297_01_aerialPhotoShadows.jpg

I’ve drawn blue lines in the screen dump that are actually the shadows being cast. And the yellow lines are drawn on the edge of the shadows in the aerial image. (101297_01_20201123-Shadows.jpg)

The buildings are modelled from the data that has been acquired from the data of November 23-24. But when I turn on the shadows, they seem to be off time-wise: more or less the situation of September 16, 2020…

In the image below you can see that the shadows almost match when I configure the shadow widget more than two months earlier. (101297_01_20200916-Shadows.jpg)

I don’t understand why this is the case. Maybe there is a plausible explanation for it? Or do we have an issue here?

Hopefully my story is clear and someone can help?

Hi all! Anyone an idea?

Does someone have encountered this issue too?

Maybe someone from the Cesium Team, @janine ?


Thank you for the question! You may be able to rotate your tileset to ensure that the shadows that are generated at runtime match the shadows in your imagery. I know that our API does its best to give accurate shadows. However, I am not sure if producing shadows that are accurate to the millimeter is a top priority.


Hi @Harmen_Kampinga,

how do you set the time in your app? If I remember correctly, Cesium time is UTC and in the Netherlands is UTC+1 in winter or UTC+2 in summer. so maybe subtracting 1 or 2 hours from your “time setting” will help? I think that 1 or 2 hours so late in the year could make such a big differance in northern Europe.

Best Lennart

Thanks @sam.rothstein and @lennart.imberg : I will have a look at your suggestions and keep you posted.

@sam.rothstein : it’s not about millimeters, actually much more like decimeters to a meter or so. They’re both off now too much. But, I’ll have a look at it.

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Thank you for the additional information - I didn’t realize the scale of the error that you are seeing. Please give @lennart.imberg’s suggestion a try and get back to us. Looking forward to learning more.


Hi @lennart.imberg and @sam.rothstein ,

tried to alter the situation by setting my date/time settings.
Time changes in my shadows settings, but nothing else happens actually.
Still it’s a month or two ‘off’ … Like having the right shadows in September while the imagery shows shadows of the date that it has been flown in November…

So, still confused here