Are ellipses essential in transferring an orthographic drawing to perspective?

iReddog

Hello there everyone; while I'm aware this is a forum more dedicated to 3D / computer design, I figured someone here could answer a question I've had since getting to a chapter on Orthographic views in Scott Robertson's book "How to Draw". I recently picked this up (deciding to go with a more traditional drawing learning path before diving into modeling), and so far, I absolutely love the book.

However, he mentions something that puzzles me. When drawing an orthographic side view of, lets say just a basic curve, he places a bounding box with equal sized squares into it.

Then, in order to get that into perspective, he uses an ellipse guide to draw the square into perspective, and then uses a rectangle multiplication technique to multiply the same distance as the ortho view.

As someone who has recently just blown >$200 on supplies for drawing (parallel glider, copic markers, pens, books, etc), I'm a bit tapped out, and would rather not buy $150 ellipse templates (holy crap, why are they so expensive!?).

But more than that, I'm very curious as to why the ellipse would be needed at all. I realize that a circle in an orthographic view is bounded by a perfect square, so doing an ellipse (which is a circle, in perspective) makes a perfect square, again in perspective, but I don't see why you couldn't just make two horizontal lines running to one of your VPs, and then just make your first box with any verticals, and just multiply.

Sorry if this is sort of rambling on, it just had me really curious, and it was the first part of the book that didn't directly have an explanation.

Thanks!

Steve Schulze

Unless you're doing technical drawing and absolutely need perfect perspective, using an ellipse template for laying out your guides is unlikely to be particularly necessary. Just freehand it - that's an important skill to learn if you're getting into this sort of drawing.

If you do decide to go the template rout, you shouldn't need the ellipse sets with 20 different arrays of ovals. A ten dollar one from your local newsagent is likely to be perfectly adequate at this stage.

Muzzoid

"How to draw", absolutley the best way to get into drawing if you take to that method! Keep this up and you'll be bounding ahead in no time.

Now that being said, scott robertson for the most part just freehands his ellipses, he just uses templates during cleanup.

I say don't worry about it too much and do it freehand

Now the reason why he is using an ellipse, from what i understand is that finding a perfect square in perspective is very difficult. But you can construct a circle in perspective easier, so you use that to find your perfect square.

That being said, when sketching you can get away with guessing the perfect square.

MagicSugar

You need the elipsee to establish the first square. Circle axis are tangent to square mid-points, right.

You need to find mid-points so you can evenly plot your construction points (if you're drafting a vehicle in perspective Scott Robertson style).

Theory is illustrated here:


You can eyeball it for sure but Scott's just giving you the "best practice" approach.

Personally, I just use an elipse perspective snap like in manga studio/ clip paint to do my elipses. Or use any of the other linear perspective rulers. Wait for the $15 sale. :thumbup:

iReddog

Muzz wrote: »

"How to draw", absolutley the best way to get into drawing if you take to that method! Keep this up and you'll be bounding ahead in no time.

Now that being said, scott robertson for the most part just freehands his ellipses, he just uses templates during cleanup.

I say don't worry about it too much and do it freehand

Now the reason why he is using an ellipse, from what i understand is that finding a perfect square in perspective is very difficult. But you can construct a circle in perspective easier, so you use that to find your perfect square.

That being said, when sketching you can get away with guessing the perfect square.

See, this is where I get confused (and I could be completely seeing this wrong), but isn't any rectangle put into perspective a square? Just depending on how wide / tall it is determines the perspective?

I was under the impression that there was always at least one ellipse that fits into any rectangle.

EDIT: Ok, after re-reading some of these replies, I think I'm wrapping my head around it a bit more. I guess if you made your verticals too tall, it certainly wouldn't be a square, even in perspective.