All Questions
Tagged with projections transformations
26
questions
2
votes
0
answers
182
views
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
2
votes
1
answer
418
views
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
0
votes
1
answer
340
views
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
views
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
2
votes
2
answers
323
views
Parallel projection is special case of perspective projection
I synchronized with @David k's first and second answer regarding perspective and parallel projection. From the first question I understand that the image on the screen is typically described in ...
user17337
3
votes
1
answer
955
views
Difference between transformation and projection? [closed]
We know that world coordinates $(x_w, y_w)$ transform to viewport coordinates $(x_v, y_v)$ which are the physical device coordinates. And during projection, any point $(x, y, z)$ projects to $(x, y)$ ...
user17337
1
vote
1
answer
85
views
Why shearing coefficients multiplying by y? [closed]
We know that shear is transformation that distorts the shape of the object. Shear relative to X-axis that is $y=0$ line can be written as:
$x'=x+sh_x.y, y'=y$
My question is why $sh_x$ is multiplying ...
user17337
1
vote
2
answers
163
views
What is this graphical effect called?
I was watching this trailer:
https://www.youtube.com/watch?v=pWh5388AEHw
and at 1:22, the player used a magic trick that created a sphere that warped the projection of the scene.
Does anyone know ...
- 113
1
vote
0
answers
253
views
Model View Projection Matrix Multiplcation Order
I'm working on a simple software renderer and have a working implementation so far. I'm curious as to why it's actually working since I would expect the multiplication ordering for my world, view and ...
- 11
1
vote
0
answers
90
views
Why does my self-written rendering engine make further away objects look larger?
I am writing a very simple rendering engine. I have already made a few tests, but somehow the images it creates look wrong. Objects that are further away from the camera look larger than objects ...
- 111
0
votes
0
answers
91
views
Consistent Video Depth Estimation from Monocular Lens to approximate LiDAR?
If the iPhone had LiDAR sensors, it would be possible to generate a 3D point cloud that you could theoretically use to furnish a 3D AR reconstruction of your surroundings. E.g. you could create an AR ...
- 101
0
votes
0
answers
32
views
Does rotating object inside unit cube [-1,1] by homogenous matrix move it outside unit cube
I am just trying to rotate my pointcloud object which is inside the unit cube ([-1,1] in all x,y,z axis). What I did is use the basic rotation matrix from wiki and extend it to homogenuous 4x4 matrix (...
- 111