3D Analyst ArcScene - no help entry on "viewfield angle"

[jimparsons]

I'm baffled to find no help entry, even in a fulltext search, on viewfield angle. This is one of arcscene's most critical settings. I'm keen to know what kind of projection is used to wrap up to 179 degrees of the scene, because with high angles a distortion is very evident.

But there's nothing at all in the help files. Why is ArcScene not properly documented?

[KentBuchanan]

I'm baffled to find no help entry, even in a fulltext search, on viewfield angle. This is one of arcscene's most critical settings. I'm keen to know what kind of projection is used to wrap up to 179 degrees of the scene, because with high angles a distortion is very evident.

But there's nothing at all in the help files. Why is ArcScene not properly documented?

I don't think that there's a traditional "map projection" involved here, the viewfield is more about camera angles - a photographer might give you a better answer.

I've got a related question, though - is there a rule of thumb for figuring out what a "natural" or "realistic" viewfield angle is?  I want to get lots of stuff on my screen (i.e. a wider angle), but I don't want to be misleading about what someone's view might actually look like when the items in our project are eventually built.

[jimparsons]

It uses normal linear perspective with a flat image plane. This means it will always be less than 180 degrees, and as you approach 180 the distortion becomes greater.

It's analogous to a painter painting a flat canvas, or a piece of glass looking through a window. Most artists suggest about 60 degrees. You are best to imagine your client observing the scene through a window. Work out the angle subtended through that window.

For large angles you either need to display on a really really big screen, or you need to put your face really really near the screen to match the centre of projection. That's why it looks distorted when viewed from a normal eye/monitor distance.

It would be nice if ArcGIS would mention these things in their documentation, but let's face it, documentation is hardly their strong point, particularly with ArcScene.

[TerryKinsman]

I have a question related to this in case anyone knows..   is the viewfield angle setting represent the horizontal, or diagonal angle of the view?

[KienAn]

Thanks for your suggest Kabucha, I known how to slove in this case