Posts: 7
Threads: 2
Joined: Jan 2012
Reputation:
0
05-03-2013, 02:40 PM
Hey daggers, I've learnt most of the basics of perspective, but I've come to a roadblock and my searches for information have proved fruitless. I'm hoping someone here knows what's up, 'cause I'm at a complete loss.
1) How do you accurately measure length in perspective? Your horizon line is whatever height your character/camera is—which is all well and good—but how can I then translate that measurement to the z axis (same measurement applied with foreshortening to the vp/s)?
2) I know 1, 2 and 3 point perspective relatively well, but not one book, article or video I've seen or read has covered objects that aren't parallel to each other (in the same scene that is). Say you draw a cube, then want a copy of said cube on the same [ground] plane but rotated. How does the duplicate then assimilate into an already apparent perspective field?
Though my questions are somewhat convoluted, I hope you can understand what I'm getting at. Thanks for reading.
- Brodie
Posts: 74
Threads: 7
Joined: Oct 2012
Reputation:
0
I'm not sure about 1, i tend to guesstimate with measurements, if it looks roughly right then i go with it. I'm sure someone else will be able to say precisely. As to 2, if you're drawing something that is not inline with the perspective grid you;ve set up...you draw (or visualise) a new vanishing point or points for this new object, along the same horizon line (if its on the same plane), but cross reference the original perspective grid to see if it falls in line with it, again you;re kind of eyeballing it for the measurement. I'd be interested to see a more specific approach to doing this too, if anyone else knows?
Posts: 227
Threads: 13
Joined: Mar 2013
Reputation:
2
hi dude, the question u pose is very technical but can be learnt, it relates to architectural (technical) perspective.
The horizon line is better if we think about this as EYE LEVEL, cos thats what it is.
basically cos the picture we are creating is flat. and our eyes are outside this flat surface. the only way to measure the distance, from our eyes to the EYE LEVEL (horizon line) in the picture plane is through something called a station point. this is an imaginary line drawn (usually) down from the eye level line outside our picture (so outside the screen u r using for ur picture.) this distance is then used to represent the distance of the viewer to the picture and it is also used to work out the scale of things inside the picture by relating them to the distance of the viewer to the picture plane.
This is very hard to explain via text, there is an awesome dvd via gary meyer which goes into this, or i think there is a book by NORLING which explains this also :)
all the best O_O O_O
Posts: 133
Threads: 2
Joined: Jan 2013
Reputation:
2
I would try to explain you but is better you watch the Gnomon dvd - Basics Drawing By Scott Robertson (he is a pro). If I'm not wrong in the dvd he explains everything related to your questions, in a clear and simple way, easy understandable.
Hope it helps :0
Posts: 227
Threads: 13
Joined: Mar 2013
Reputation:
2
scott robertson is a great teacher, and the dvd is incredible and well worth watching, though the answers to your question arent in there. Also in regards to the cube. If u rotate it, that cube now has a different set of vanishing points, different to the rest of the scene. :)
Posts: 7
Threads: 2
Joined: Jan 2012
Reputation:
0
eZTarg8: That's pretty much where I'm at. I can make guesstimates easy enough, but I'd like to know how to do it accurately as well. :-)
YOLOLEX: I knew it had something to do with a Station Point, but couldn't find a reliable source. Thanks for the tips, I'm looking them up now!
On the rotated object: I've figured out that they require a different set of vanishing points, but the questions remains on where those vp's should be. One theory is that in two point perspective, they carry over the degree at which the vp's meet. Just a theory for now though.
Blewzen: As YOLOLEX mentioned, unfortunately he doesn't cover the information I'm searching for in that dvd. I've watched and learnt much from that one though. He's an incredible teacher (and artist).
__________
Thanks for all the suggestions everyone. :-)
Posts: 227
Threads: 13
Joined: Mar 2013
Reputation:
2
u have to find them with the rotated cube sides follow the angles till they create a vanishing pt.
Posts: 7
Threads: 2
Joined: Jan 2012
Reputation:
0
Things have been a bit hectic this last while for me. Sorry for the slow response.
YOLOLEX: My questions drills down to what information the duplicated (but rotated) object carries over. Having contemplated this a little more, I realised this issue will be solved once I figure out the first question. :-)
______
Does anyone know of any free, online resources on technical perspective by chance? I'm willing to cough up the cash if need be, but I'd rather avoid that if possible.
Sorry to be a pain.
Posts: 7
Threads: 2
Joined: Jan 2012
Reputation:
0
Thanks! I've only had a cursory glance at the site, but it looks like it may have exactly what I'm looking for. Much appreciated. :)
