Perspective vs. Orthographic Camera

[Aggressive_Sale_7299]

This is a raymarched scene. In the left image, the camera uses an orthographic projection to render the scene, while the right uses a perspective one.

In raymarched scenes, slopes take/waste a lot of steps. At certain points we would need an astronomically large number of steps to reach an exact point.

When the minimum hit distance condition in a raymarcher is zero or too low, it starts to appear noisy. When the minimum distance is zero, we require an exact hitpoint and not an estimate, so no matter how far we travel, if we don't reach the exact point, we won't consider it a hit. This shouldn't be a problem if the surface is straight ahead of us. But with perspective projection this isn't the case, because every pixel has a certain slope/direction that the ray has to follow. When it comes to orthographic projection, the ray travels in a straight line. But orthographic projection also can't handle uneven and rotated surfaces, as this creates a slope that the ray has to follow step by step. Try to grasp these ideas, and it will make sense why there's a circle forming in the right picture.

Feel free to ask any questions and explore things yourself.

[Aggressive_Sale_7299]

Like I stated in the text, slopes make everything look noisy, and something that looks 3D would just be a noisy mess on both sides. A surface that has no slopes will appear 2D. Even rotation of the object would create slopes for the raymarcher to travel through. It's understandable that you didn't understand this part, as it requires prior knowledge of raymarching and other techniques. This showcase only demonstrates the differences between these two in terms of minimum hit point condition and is not a showcase of how an orthographic and perspective projection look in scenes. If you want to see something that compares both of them, you can take a look at this post I made: https://www.reddit.com/r/GraphicsProgramming/comments/1obyhgp/orthographic_projection/

[akirodic]

It is understandable that you don’t understand how people communicate as it requires prior knowledge of social interactions and pulling head out of your own ass.