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Guest Sethelic

How To Use Ellipse Templates In Perspective Drawings?

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@Cyberdemon -

even if u get different sizes, how do you determine which degree of exposure template do u decide on?

 

I draw all of my ellipses freehand, then to clean them up I simply find the closest ellipse that I have and use that.

 

Sketching isn't about being perfect to the exact degree of ellipse. Sketching is about conveying something to the eye, and while a very very wrong ellipses is easy to spot, an ellipse thats only off by a few degrees will look fine as long as it's correctly aligned in perpective.

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Guest Sethelic
@Cyberdemon -

even if u get different sizes, how do you determine which degree of exposure template do u decide on?

 

I draw all of my ellipses freehand, then to clean them up I simply find the closest ellipse that I have and use that.

 

Sketching isn't about being perfect to the exact degree of ellipse. Sketching is about conveying something to the eye, and while a very very wrong ellipses is easy to spot, an ellipse thats only off by a few degrees will look fine as long as it's correctly aligned in perpective.

 

 

hmm.. i'm beyond the sketching stage now where i am trying to pinpoint exact accuracy for the rendering stage.

 

you mention using an ellipse template, is it possible to create a correct circle in perspective just by using the template? it seems from the tutorials i see, perspective circles requires some slight modifications from the ellipse produced by the templates. whats your say?

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Yes, you can create a correct circle in perspective with a template provided your drawing uses a degree that you have a template for. Otherwise you'll have to make a slight approximation.

 

You don't need to pinpoint accuracy for the rendering stage. 2/3 point perspective isn't accurate. It's an artists approximation because you can't accurately recreate the way our curved eye sees the world.

 

The most important part of any drawing is that it READS correctly.

 

What tutorials are you looking at that "modify" the ellipse? The only thing I can think of is varying the line weight for a good ellipse. IE drawing the dark side very thick and then fading the line out to nothing on the opposite side to indicate a highlight/shadow.

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Guest Sethelic
Yes, you can create a correct circle in perspective with a template provided your drawing uses a degree that you have a template for. Otherwise you'll have to make a slight approximation.

 

You don't need to pinpoint accuracy for the rendering stage. 2/3 point perspective isn't accurate. It's an artists approximation because you can't accurately recreate the way our curved eye sees the world.

 

The most important part of any drawing is that it READS correctly.

 

What tutorials are you looking at that "modify" the ellipse? The only thing I can think of is varying the line weight for a good ellipse. IE drawing the dark side very thick and then fading the line out to nothing on the opposite side to indicate a highlight/shadow.

 

The khusley.com site & also a technical illustrator book. How do you even determine your ellipse is of the right degree for your drawing?

 

What do you mean by degree of your drawing? Is it based on the VP of its wheel axis? or its the degree of the ellipse is facing itself? because i thought ellipses change in exposure when they move away from the center of vision, so two ellipse in plan view which are of the same tilt but placed at different horizontal distance from viewer would appear to have different tilt?

 

I understand that circle in perspective is still an ellipse with different center point, and thats why i've been trying to find out too. Say when i use a ellipse template of 25 degrees in perspective drawing , how do i relate that 25 degrees to the drawing .i.e which drawing component to use as reference for the 25 degrees, since ellipses ain't always centered in frt of the viewer and may change degrees due to horizontal distance too. I'm really confused about it man, i thought of using the wheel axle as ref but seems like i cant figure it out either.

 

i asked around in several forums , seems like no one seems to want to tell me that either =( if only someone can enlighten me..

 

do you know of any other industrial design/architecture forums where i can try asking other technical qns too?

 

Thanks

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Honestly I can't give an answer to your question because I'm not really sure what you're asking or how to answer it.

 

I don't determine the numerical degree for anything, I'll sketch in a rough ellipse so that it looks good (even if it isn't correct) and then use the closest thing that matches it on my template to fix up the lines (or do it digitally). Scott Roberston does a good job on his perspective DVD's going into ellipses.

 

Outside of that I don't really know what to say.

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Guest Sethelic
Honestly I can't give an answer to your question because I'm not really sure what you're asking or how to answer it.

 

I don't determine the numerical degree for anything, I'll sketch in a rough ellipse so that it looks good (even if it isn't correct) and then use the closest thing that matches it on my template to fix up the lines (or do it digitally). Scott Roberston does a good job on his perspective DVD's going into ellipses.

 

Outside of that I don't really know what to say.

 

 

Thanks :) you've already been a great help. I was wondering since manufacturer's produce different degree of ellipses, there must be a systematic way of determining which numerical degree ellipse to use in different situations in Perspective drawing rather then just finding a closest one to match. So i am interested to learn that.

 

I watched the dvd, but he makes no mention of how you systematically determine which degree of ellipse to use, i suspect its because it was a basic perspective drawing dvd.

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Guest Nathan

Sethelic,

 

See if this makes any sense:

 

post-8092-1173234526.jpg

 

When you look at a circle straight-on it looks like a circle. When you revolve it along its central vertical axis (without tipping it) it looks like a regular ellipse. How elliptical it looks is driven by how much you revolve it. The degrees printed on the template indicate that this is what a circle would look like when viewed at x angle--no perspective applied. To apply perspective you would need to tip that central axis the same as you would a straight edge (and even deform it along its minor axis depending on how much perspective is applied. The templates aren't so much for perspective as vantage point and are generally used just as aids to help your hand create what your eye sees is right.

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Guest Sethelic
Sethelic,

 

See if this makes any sense:

 

post-8092-1173234526.jpg

 

When you look at a circle straight-on it looks like a circle. When you revolve it along its central vertical axis (without tipping it) it looks like a regular ellipse. How elliptical it looks is driven by how much you revolve it. The degrees printed on the template indicate that this is what a circle would look like when viewed at x angle--no perspective applied. To apply perspective you would need to tip that central axis the same as you would a straight edge (and even deform it along its minor axis depending on how much perspective is applied. The templates aren't so much for perspective as vantage point and are generally used just as aids to help your hand create what your eye sees is right.

 

Thanks for the picture.

 

1. I was wondering about the template vs perpsective circles as well. It becomes confusing, when i try to include perspective as even ellipses of the same revolvement changes in degrees as it moves away from the center of vision. so i was wondering is there even any underlying mathematical relationship where i can calculate them out & use the templates as well without any modifications by hand?

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Guest Nathan

Quick answer: No.

 

Long answer: The templates are for isometric drawings which are created with no perspective applied. All receding lines stay parallel to each other rather than trend toward a vanishing point. Learn to draw cubes with perspective applied and then use them as guidelines for building proper ellipses. Scott Robertson outlines this technique very well (in a way that might seem more drafting/mathematical) in this book. Everything pretty much boils down to practice though.

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