08-02-2012, 06:58 AM (This post was last modified: 08-04-2012, 05:07 PM by williamj.)
Chris,
I agree, somewhere out there, there is a mathimatical formula that will pricisely place all objects within the building outline with proportionately diminishing widths. Not being any kind of a mathimatical genius (boy do I wish I had stayed awake during math) I think we can do this with out reverting to Pi R(squared) or E=MC(squared).
Great thinking on using an arc, I believe that puts us more on the right track.
Using the arc got me to thinking...
The vanishing point path is, in reality, a linear slope (I.E.( x1,y1),(x2,y2)). And we were trying to place our dimenisional markers along this linear slope. Instead, what we should have been using to place our markers is a curve (I.E. ab+c). And from these markers place our lines of distance along the vanishing point path. (I think)
Gonna go work up a drawing or two to illustate and will let you know how it turns out.
I really think that this is a go. The procedure presented int the attached PDF puts the building in perspective and the windows and door also show perspective. The windows and door do show, what appears to be, proportional diminishing width.
I doubt that this mathematically correct but for visual presentation it's pretty close.
Uhhh... hope you don't mind but I put your name on it too. It is mostly you fault. If you hadn't decided to play with arcs this probably wouldn't have happened. So it's "ALL" your fault!
Quote:hope you don't mind but I put your name on it too. It is mostly you fault. If you hadn't decided to play with arcs this probably wouldn't have happened. So it's "ALL" your fault!
No Problem Bill, your use of the arc strategy is a little different, but as you say I think we're closer to getting what we want this way. I did a little googeling to see if there truly was a mathematical solution and found out that there was, just more complex than what the average cad draftsman would find useful.
08-07-2012, 04:34 PM (This post was last modified: 08-07-2012, 04:51 PM by Admin 1.)
I've been following this discussion since it stared. I enjoyed seeing the 'trial-n-error' methods that both of you have trying. - Good job!
There is a way, however, that requires virtually no math at all. What you need to do is establish a 'View Point'. [HINT} -- front/left --- front/right ---- back/left --back/right --- or any other viewing angle from top-to-bottom or side that you can think of.
I'm working on a "thing". (It's not a tutorial... yet), but once I understand it, (and succeeded with doing it myself... lol), Then anyone should be able to draw a perspective drawing using DeltaCad from any angle they choose.
FYI: I'm using, as a reference source, an old copyright 1976 .. pre-CAD, school book. So yea , the info is 'old' but the concept is totally on track.
I can tell by your changed signature that you had a good time at the airshow.
You got me thinking after you mentioned using an old textbook that maybe I was searching for the wrong information. After googleing "drawing perspective" my search came up with a net full of goodies! Still, I had to delve deeper to get what we've been aching to learn. What we should have been searching for was not just how to draw in perspective, but how to draw a "foreshortened" view.
Check this out....(Bill, you're going to LOVE this!)
Wish I would have found it sooner!
WOW! and I thought I had a headache before!!! (LOL) I never once thought that this would be anywhere near as involved as this has turned out to be. And I want to thank everyone for all their efforts and valuable time. Thank you.
I agree whole heartily that this should end being as simple as possible so that anyone, using DeltaCAD or any other 2D cad program, could use and end up with a proportionate perspective, and reasonably accurate, drawing. Atleast visually balanced if not mathematically accurate.
As part of all this, I've been looking into isometric drawing (never done those before either (LOL)) as well, it in fact being a drawing in perspective (at a fixed vanishing point vector of 30 degrees). And I noticed that there is no diminishing depth as there is no diminishing width in other perspective drawings. At this point I don't think that helps anything but I thought I'd mention it as an observation.
And Chris, you're right, I do love it! (LOL) Somehow, someway we have to tie all this together and end up with a fairly easy way to achieve our goal.
(08-07-2012, 11:08 PM)i44troll Wrote: Bill,
Perhaps we should have started with drawing in isometric. It is so much easier to do.
Chris,
For me it's all "chicken or egg", and in all probability the perspective predates the isometric (chicken then egg). If memory serves (more often than not it doesn't), the first time I ever heard terms like prespective, horizon line , vanishing point and yes "foreshortened view" was in an art class and not in a math class.
And speaking of "foreshortened view" I made some "velly intorestink" observations last night playing with your foreshotening process. It's a curve, when the diminishing distances are taken and plotted on a graph the resulting slope is a curve. An almost one hundred percent perfect curve, and the radius of that curve is very close to the length of horison to vanishing point in the foreshortening view. The correlation between that and the curve used in the perspective drawing blows my mind!
I'm working on some drawings. I don't want to base my presumptions on just one or two observations so I'm going to do several at different distances and see how everything holds together, or doesn't.
Will get back with you when the drawings are done.
I've learned quite a few things messing around with the foreshortened view prospect. First of all, the foreshortened view, when graphed, is indeed a circular acr. Which leads me to believe that we are indeed on the right track by utilizing a radiused arc in laying out the vertical layout lines. Also learned was the fact that the radius of that circular arc is soley dependent on that first parrallel line in the foreshortened view developement.
One very important lesson, when trying to intergrate a foreshortened view into a perspective is that all measurements along the X dimension must be increments of that first parrallel line measurement. If they are not then not all of the finall lines will be proportionally diminshing.
I've attached a PDF that, I hope, will show how to get proportoinally diminishing line all the way across.
08-15-2012, 01:22 PM (This post was last modified: 08-15-2012, 01:25 PM by williamj.)
After finally reading about circles in perspective, (reference by i44troll in an earlier post) I included a circlular adornment in this next effort, as well as a slight change in procedure. I hope I explained it all well enough that it is understood. Also, if my failure to maintain consistant nomenclature through out this thread is problematic for some, I appologize. I blame that failure on my poor communication skills.
Stating that it is a pain (he didn't say pain, I forget what it was he actually did say but it wasn't pain) to utilize a picture from a PDF in a DeltaCAD drawing, "theBoss" has graciously permitted me to, temporarily, include DeltaCAD files (.dc) in this particular thread. (Thank You Boss)
Please let me know if the attached does or doesn't make sense,
williamj
