Relatively simple perspective question

[Allan Rahbek]

Chuck is right.

To get the measures right you will have to place the "glass plane" at the distance from "viewpoint" by the "A" line.

Allan

[Geary Wootten]

Ya gotta love it when guys say' , 'This is easy", and then go into partnership with geometric theory. LOL!

In 99% of my drawings and paintings, I FAKE it baby!

-Gear (Just clowning w/ my 2

[Ken Smith]

I think that technique is called "plan perspective." (I read three different books on perspective last evening). And that seemed to be the only way to get the info I was looking for.

I was hoping for something simpler, because I'm not actually drawing a cube. I'm drawing the inside of a boat cockpit.

I've also heard this referred to as descriptive geometry. Keith Ferris, the aviation artist, says he uses it to draw exotic angles on fighter planes (from blueprints). One of my perspective books has an example of an airplane in a box drawn this way, but frankly I can't make heads or tails out of how they've explained it.

It has nothing to do with portraits, but if any of you know of any books that explain this technique in English (particularly as it applies to objects more complicated than a house), I'd like to read one.

[Allan Rahbek]

Hi Ken,

I am, by no mean, interested in oversimplifying things. But I insist that you can draw anything by looking through an imaginary frame from a particular viewpoint. Just try it!

When I draw, I control my drawing by comparing the angles with the vertical and horizontal of the drawing paper.

Next, I often draw life size, to bee another control funktion .

This, of cause, are technical things that have to bee understood before you can take the advantage of them.

There are many topics that deal with these matters.

Ken, I am aware that you are the one that just asked the question, but I prefer to answer as precise and direct as I can.

Allan

[Chuck Yokota]

Ken,

Um, I guess I thought it *was* the simple way. I got my stuff from a course in geometric modelling, a graduate-level engineering class in the mathematics behind how computers generate real-time 3D scenes onto your monitor. The course started out assuming you were familiar with matrix algebra, vector and tensor calculus, and differential equations, and then got into the complicated stuff. Plan perspective was tossed out as a simple, intuitive way to picture what was going on when the computer was crunching bits.

As Allan says, you can paint any scene by painting through an imaginary frame, from life.

I suppose the next simplest way is to use a reference photo and accept whatever distortions are created by the camera lens.

[Steven Sweeney]

Limiting this response to the desired representation that was described

[Geary Wootten]

Originally Posted by Steven Sweeney

.........Voila, and it hardly even hurt.

......Qww - ya wanna bet? LOL.

Steven, Ken..et al,

Thanks for taking the time in doing this. In spite of my yucking it up, I actually learned some things today.

G. (reeling from left brain hook to right brain. )

[Steven Sweeney]

So, okay, I added the supporting illustrations above. That

[Allan Rahbek]

Steven

There is no "true" perspective, all of them are theoretical, fulfilling different needs. I try to avoid the use of linear perspective.

How did you place the two vanishing points ? Did you measured them to the right place or how ?

I think Ken will have troubles drawing in a small boat cabin. It is tempting to take a broader view when drawing in a small room. When seeing the drawing from a longer distance (than it was done) you will see distortions.

I will attach a drawing that, hopefully, will explain the perspective consequence of doing the wide angle view.

Allan