All Questions
Tagged with projections 3d
35
questions
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19
views
How to extract points corresponding to faces from cube map projection (CMP) of panorama from point cloud data
I am working with the standford2d3d dataset http://buildingparser.stanford.edu/dataset.html which contains panoramas of various scenes and a .mat file of the point cloud information of all the scenes. ...
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31
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Object appears in unintended parts of the screen when using manual WorldToScreenPoint
Hy guys I'm new to 3d graphics and i lack some Linear algebra knowledge. I tried to recreate Unity's worldToScreenPoint method with kotlin on android. I copied some code from their forum and wrote ...
- 1
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37
views
3D engine projection distortions
I'm trying to write my own 3D engine using Python and Pygame.
I have successfully implemented rotation and projection matrices to display 3D models. However I am so far unable to implement translation ...
- 11
2
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182
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Finding Camera projection matrix from known input and output
Lets say I have a rectangle with known coordinates in 3D scene, and I'm projecting it using pin point camera to the plane (screen).
You can imagine it deforms on the screen per camera transformation ...
1
vote
1
answer
72
views
What fields should a camera class have?
For a good and scalable project structure, what fields would you add to a camera class, apart from its position and orientation? Should I add the near and far planes? Or should that be global, what ...
- 113
4
votes
1
answer
1k
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How to derive Field of View (FOV) angles from a 2D projection
I'm looking for some guidance.
I'm not sure if this is possible, and I'm not sure where to start.
I need to measure the FOV angles of a first-person, 3D game using only gameplay screenshots.
I'm bound ...
- 51
-1
votes
1
answer
171
views
Why we calculate z buffer value from plane equation $AX+BY+CZ+D=0$?
Suppose in perspective projection $(x, y, z)$ coordinate projects to point $(x_p, y_p, z_{vp})$ in projection plane $AX+BY+CZ+D=0$ where projection plane kept at $z_{vp}$ position. And the plane $AX+...
- 211
2
votes
1
answer
418
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3D homogenous coordinates versus 4D homogenous coordinates
We know that any 2D point $(x, y) $which represents as 3D homogeneous coordinates is of the form $(x, y, 1)$ which is the points of projective plane $P^2.$
If I use the same concepts for 3D points $(...
- 211
3
votes
2
answers
277
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$(x, y, 1)$ is 2D homogenous coordinates or 3D homogenous coordinates?
We know that $(x, y, 1)$ are the homogenous coordinates of a 2D point $(x, y)$. $(x, y, 1)$ has 2 degrees of freedom. That's why we should call it 2D homogenous coordinates. But many websites say it's ...
- 211
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340
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Perspective transformation is perspective projection? [duplicate]
I know that (
Reference )in transformation source and destination has same coordinates dimensions. But in projection destination coordinate system has fewer dimensions than the source coordinate ...
user17337
1
vote
5
answers
2k
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Existence of vanishing point
Consider the following example of perspective projection: I have one railway track with two parallel lines meeting at the point $X$ at infinity which is the theoretical approach. This X is called the ...
user17337
1
vote
0
answers
68
views
3D shearing w. r. t $x$-axis [closed]
Shearing in $X$ axis is achieved by using the following shearing equations-
$X_{new} = X_{old},
Y_{new} = Y_{old} + Sh_y × X_{old},
Z_{new} = Z_{old} + Sh_z × X_{old}.$
My question is during $Y_{new}...
user17337
3
votes
1
answer
848
views
Difference between 2D and 3D pipeline
2D transformation and viewing:
The camera projects the 2D world co-ordinate $(x_w, y_w)$ on its projection plane which co-ordinates $(x_v, y_v)$.
3D transformation and viewing:
The camera projects the ...
user17337
1
vote
2
answers
306
views
Difference between perspective and parallel projection [closed]
We know that in orthographic Projection Projectors (projection vectors) are perpendicular to the projection plane.
And in Perspective Projection Object positions are transformed to the view plane ...
user17337
2
votes
1
answer
220
views
$P^2$ vs projection plane
I want to explain what I understood of definition of the two things.
Projection plane:
The general processing steps for modeling and converting a world coordinate description of a scene to
device ...
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