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/ic/ - Artwork/Critique

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3465107 No.3465107 [Reply] [Original]

redpill me on major axis and centre of perspective

why use flat space measuring points instead of perspective ones anyway?

>> No.3465144
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3465144

>>3465107
eh?

>> No.3465419
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3465419

>>3465107
Because of orientation and practicality. There are multiple ways of fitting a ellipse inside a square in perspective incorrectly. You're even more likely to make a mistake if the square is in 3 point perspective.

Your priority in drawing an ellipse is to show the direction the plane is facing.

>> No.3465431
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3465431

What just happened here?

>> No.3465441

>>3465107
Only a retard would use that axis method instead of either eyeballing it, or using a 3d software
There's your redpill

>> No.3465640

>>3465419
Aight. Thanks.

>> No.3465709

>>3465441
Yeah I love not knowing the rules before attempting to use them in an abstract way.

>> No.3465718

>>3465709
you know linear perspective is just a way of approximating fixed point perspective, so you should really learn the lens formula if you want to actually understand the rules. linear perspective is an artistic convention, not geometry.

>> No.3465750
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3465750

>>3465718
Fuck, now I gotta learn sinus just to draw a box. Well god damn.

>> No.3465769
File: 66 KB, 1644x1672, perspective study.png [View same] [iqdb] [saucenao] [google]
3465769

>>3465107

>> No.3465883
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3465883

>>3465718
google says fixed point perspective means pic related. should I believe it?

>> No.3465948
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3465948

The fuck you guys talking about?
Did OP get his answer yet? If so, which post?

>> No.3465958

>>3465948
see >>3465419
basically
>why do I need the points of contact between a square and the circle inside it?
>because otherwise there could be a million different circles that would fit inside that square

>> No.3465961
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3465961

>>3465883
perhaps i used the wrong phrase, or it means more than one thing, i mean perspective as seen from a single view point. in pictures you don't need to use one view point, you can simulate a camera pan for example, so using linear perspective isn't a universal rule for drawings. that was my point, i think. or was it that there's more accurate lens calculations you could use for the same thing, so thinking of linear perspective as the rules, when it's just an inelegant description is idk lame or something.

>> No.3465962

>>3465958
Thanks. Where does one usually happen upon this concept? Don’t most books and even Eric Olsen even just eyeball ellipses (and then use a template once you “find it”)?

>> No.3465966

>>3465883
https://en.wikipedia.org/wiki/Perspectivity

>> No.3465978

>>3465962
Sorry, I messed up. It's the T-method in Perspective Made Easy for cylinders. It says the red lines in below should be roughly parallel, allowing you to freehand ellipses.
https://www.geogebra.org/m/vxCX4nmt
But if you have four points of contact that the ellipse must run tangent to, there can only exist one ellipse that fits that criteria.
http://www.math.nus.edu.sg/~graeme/Geometry/Circle_in_Perspective/index.html