Included 3D Model Offsets

Alexander Mitchell's picture

Hi all,

I remember from long ago a discuss about the fact that centre point of the included 3D models in QC is not centre. Hence why you can see the model at 0,0 even though the camera is at 0,0.

Can anyone point me in the right direction to how much distance you need to move the model to get to 0,0? So that the camera is INSIDE the model looking out? I need to get it spot on for some 360º VR Cube Mapping. Important to know offset of Sphere and Cube (which I believe is the same offset).

Right now I am using 1.732, which works by eye, but I would like to get it %100.

Attached is the application I am working on- in goes CubeMap / Equirectangular - out goes CubeMap, (with control over PITCH/ROLL/YAW).

Cheers, Alex

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Screen Shot 2015-05-14 at 3.37.21 pm.png
Screen Shot 2015-05-14 at 3.37.21 pm.png574.41 KB

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ahoeben's picture
Re: Included 3D Model Offsets

If 1.732 looks right, I would guess the real value is sqrt(3). But I don't know the reason for it being the square root of 3, other than it being the length of the bisector of a equilateral triangle.

Alexander Mitchell's picture
Re: Included 3D Model Offsets

I didn't even think of 1.732 being sqrt(3).

That does sound like a "Quartz Composer" sort of number. It is working for now- but if anyone knows for sure please post here! ;-)

Also if anyone knows where the models live (Cube - Sphere etc...) please share.

Cheers, Alex

Achim Breidenbach's picture
Re: Included 3D Model Offsets

Actually its because QC is using a horizontal FOV of 60° and a "2 units" wide base: to calculate the distance of the camera from the drawing plane you need to use the half of the FOV, calculate its tan and norm it to the half width "1 units": 1/ tan(30°) = 1.732