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Guest Felix Grossar

Ellipse Value...

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Guest Felix Grossar

Hey

 

 

Can someone tell me how to find the right value of an perspective circle (ellipse)

 

Just made some sketches and everytime I tried to make an ellipse it didn't fit to the whole sketch...

 

 

 

Can someone help me???

 

 

thx felix

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This is how I have understood it.

post-17257-1202143773.jpg

So if you look from the top of a car for instance, if the view angle on the tire is 45 deg. you then use the 45 deg. elipse. A view of 90 deg is then an entirely circular elipse.

 

On the sketch the proportions are shown on the different angles if the circles are seen from above.

 

At least this is how I have figured out it works. I could be wrong though. But for me it makes sense :)

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Guest Felix Grossar

Thank you

 

But I meant if you already have an 2 point perspective sketch (for example a camera) and you want to draw the lens of the camera.

 

How do i find out the right value or angle of the ellipse???

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I think it would be easier to answer the question if you provided an example of what you are talking about. Perhaps it more a question of aligning your ellipses with your perspective and vanishing points.

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Draw a light elipse by alligning the guide to your minor axis to your best estimate. Then draw a box around it using your perspective. The elipse should touch each side in the middle (considering forshortening, find middle by finding the center of the box). Now find the right size and angle with your guides. You can also do the box first. Note the angle for when you retrace the sketch so you won't need to do this all over.

 

Sorry for bad figure, done with touchpad.

post-4452-1202217596.jpg

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