How works Scale in V3d_View ?

I have to create a photo realistic image of a “3d_view” (OCC) with a ray tracing engine.

I have already get objects from the scene, and I would like to understand better how the position's camera works in OCC. (perspective model).

Eye and At define the direction in which the camera look at, right ?

Up indicates the direction of the top of the “image plane” (the view)

It seems that Focale is the distance between FocalReferencePoint and the “projection plane”, but I'm not sure...

I understand that a shorter Scale gives a wider view while a longer Scale zooms in for close-ups.

But what is Scale based on ?
I mean, is it a ratio between two “items”( FocalReferencePoint, Eye, At... ) of the camera or other thing ?

Thank you in advance.

Best Regards


PS : The raytracing engine I use doesn't have “Scale”. That's why I'm trying to re-interpret it.

JALLON's picture

Hi Lionel,

Have you solved your problem? I try to do the same thing...


Tilman Leune's picture

From what i have seen, I think the view's scale is related to the glScale-function from the OpenGL library.

It is used to scale the entire scene by a factor, so it does not seem to have any relation to the View eye and at - coordinates.

Setting a scale to something different from 1 leads will scale the display of your current sceneFrom your current viewpoint: All objects (and there positions relative to your viewpoint) are 'inflated' or 'deflated' by the scale factor.