Perspective question: I have height need same length/width

[mirskov]

Guys ,

is there a quick way without the ellipse to determine B if i have A. (without guessing of course). A must equal B

Can someone explain - Thanks for your help

Attachment 800993

[Elwell]

Honestly, I can't tell exactly what you're trying to do with that ellipse, since it isn't properly drawn. If A=B, then how long B appears relative to A will depend on the angle of view. B could theoretically be any length and appear correct, as long as it was shorter than A.

[mirskov]

Hi Tristan

Attachment 801021

I'm rotating line A around its pivot (center of the the ellipse) that would give me the line B - Then C (B in previous)

I believe you're right it would depend on the cone of vision



how would you guys tackle something like this if you needed to find this length but didn't have the viewing angle (cone of vision) established.

thanks for your help!

[rembart]

From the basis of A we draw a horizontal segment A '
A = A 'because they are in the same level
Then there is A '/ 3 for the point j
one draws Mj
we obtain G and plot vertical GD
and finally we draw G GO
This gives us the point K
we have B you seek




oh I did that with a single vanishing point

and it is also interesting

whole problem and design a cube in oblique perspective

I will get two points

[mirskov]

rembart - thanks!

why did you divide A' in 3 to find j

[rembart]

yes, but in the case of two vanishing points
must use the method of g / 3




because we can not divide a segment perspective into three equal portions

[mirskov]

can you illustrate when you have time

i don't think I'm following ..

thank you for your help

[rembart]

Dividing by three
that's what we discussed but I also do not know why and even our teacher of perspective do not know

I hope we find the answer

[rembart]

in a square in front
a circle through the purple points
and for this we divide by three
INSURED you about it