Computer Graphics Stack Exchange
Computer Graphics Stack Exchange

Questions tagged [projections]

Questions about the conversions of a 3D model to a 2D model.

131 questions
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1 answer

Materials for research on spherical projection

I am currently doing a research on projection on a sphere, specifically for NOAA's project Science on a Sphere. What I'm trying to do is to find out how exactly do you create a video material for such a device, because it's not as simple as making a…
Michal Kučera
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5
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1 answer

Am I calculating perspective projection correctly?

If I have a point in world space: (wx, wy, wz) and I have a centre of projection: (cx, cy, cz) and I wanted to project that point using perspective projection would my point on the screen be calculated by: x = (cz * wx) / wz y = (cz * wy) / wz I…
S.A
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4
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2 answers

2D projection from some points

I am going through an undocumented function that takes in three points and a Z-value that projects three points on the plane defined by Z-value. I want to understand the mathematical theory behind it and I need your help to decode the…
sajis997
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How to use GetViewProjMatrix().TransformVector(LineDirection) in UE4?

I try to project a 3D vector (a direction, not a position) in screen space, but it does not return satisfying results: FVector LineDirectionOnScreen = EdMode->ViewMatrices.GetViewProjMatrix().TransformVector(LineDirection); FVector2D…
arthur.sw
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3
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1 answer

Formula for cubemap resolution for intended equirectangular resolution

Suppose I want to render out 6 cubemap cameras (90 degree FOV etc.) with the intention of combining them together in post-production into an equirectangular (latlong, 2:1) image. Suppose I also know the intended final resolution of the…
kinkersnick
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1 answer

How is orthographic projection used in computer graphics technically classified as a projection?

I'm wondering why the orthographic projection we use in computer graphics is called a projection, if all it does is just scale and translate a mesh? According to wiki orthographic projection is Orthographic projection (sometimes referred to as…
Lenny White
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0
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finding the projection matrix for one point perspective

I found the derivation for two point and three point perspective here on this site, even though it says review on one point perspective, it doesn't give a link to previous pages, but I'd like to know how the matrix for one point perspective was…
mathmaniage
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perspective projection transformation matrix

In one text, the derivation for perspective projection goes like this: If $x',y',z'$ represent any point along the projection line,and $x_{prp},y_{prp},z_{prp}$ are the projection reference point,…
mathmaniage
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0
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viewing direction vectors are not parallel in orthographic projection

I did some math with orthographic projection matrix to compute viewing direction vectors in screen space. I thought all viewing direction vectors should be parallel in orthographic projection because, in orthographic projection, eye sight lines will…
slyx
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computing sheared perspective projection matrix

is it possible to calculate a "projection matrix" which is sheared as well? the usual perspective projection matrix forms a pyramid where the near clipping plane is rectangular. I have 4 lines which represents the edges of the pyramid in general.…
Thomas
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Can surface normal be used for obtaining points on a plane?

Excuse my wording. I will use the picture below to explain what I mean. I want to use the surface normals for each arrow shown like below to draw lines parallel to each plane like the image shown below the first one. Therefore I want to obtain point…
user1696420
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