# Projection drawing...

 08 August 2012 receptor Veteran   portfolio Emil Assarsson Malmö, SE Projection drawing... I'm about to write a more in depth tutorial about projection/perspective drawing. My plan is to create something that gives insight how viewpoint, "paper" and vanishing points really works. Are there something you have questions about? Is there a need for this tutorial? share quote
 09 September 2012 DanielBrown New Member portfolio Daniel Brown Victoria, Canada I know that I would be interested in reading it. Perspective is one of the most confusing things I have ever tried to understand, with conflicting methods that only work well in limited scopes. I still don't have a perfect grasp of perspective, but I am trying to understand it. I have come up with some solutions (reinvented the wheel) to some of these problems, but I am still scratching by head about some things. I am curious to how you present your answers, because I know my explanations are dificult for people to understand. The list of questions that I had, and which I assume bug other people: -Locating vanishing points, how do we know where they go? One, two and 3 point systems. Trying to locate the 3rd vanishing point is rather tricky because it moves. This drove me nuts. The closer the object is to the horizon, the more vertical the objects and the farther the 3rd vp gets from the horizon. -How to actualy draw a square, and a cube. This is my simplest explanation, it explains the location of the 3rd vanishing point, drawing a square and a cube: http://reflective-sentinal.devianta...-cube-329293520 -Assuming my diagram is correct (which it certainly might not be, or I may be interperating it incorectly), why there is twice the angular distance verticaly than there is horizonataly. I don't know that it matters, but it .. bugs me. I probably have something wrong here somewhere: http://reflective-sentinal.deviantart.com/#/d5g7tg3 More complicated stuff: -First example: Two 6 sided dice on a table, rotated randomly. The vanishing points on the horizon move according to plan view, while the z axis remains shared. We can compare the size of the dice by looking at the z axis, and transfering the scale measurement between the dice like a 1 point perspective system. -Second example: Take the same two dice and roll them. As the dice tumble through the air, none of the axes line up, making it rather hard to compare locations of vanishing points or compare sizes of the cubes. I don't have a way to simplify this one.... probably one of those things to throw into a 3d program for practicality, but there should be an answer somewhere. share quote
 10 October 2012 receptor Veteran   portfolio Emil Assarsson Malmö, SE Thank you for your reply. I believe that perspective drawing have been mystified by strange methods and inaccurate simplifications. Please try to look at my method with fresh eyes. This is my method of perspective drawing: https://docs.google.com/folder/d/0B...Z1dMT0plVXVZS28 I use this method to verify my conclusions about how perspective works. The method is too slow to do something more complicated (like the two dices) with and it can't be a part of a creative process. The conclusions is a different matter: As you can see, it's possible to draw perspective without using vanishing points (vp) or a horizon. In real life vp's are really helpful and you only need to know why they exists to be able to estimate the placement of them (I write "estimate" because sometimes they will be really far away). *If* I have managed to explain how perspective works in this PDF properly you will be able to make a conclusion about where you should place the vp's. I don't want to give the answer away yet because I want to know how well it works :-P You will notice how the viewers eye, the frame (picture plane, paper or canvas) and the object placements, rotation and tilt are equally important. share quote
 10 October 2012 receptor Veteran   portfolio Emil Assarsson Malmö, SE This is an experiment with the method and may be too messy :-P https://docs.google.com/file/d/0B9r...kNzX2c3b2M/edit share quote
 10 October 2012 receptor Veteran   portfolio Emil Assarsson Malmö, SE Andrew Loomis book Successful drawing holds a number of interesting conclusions about perspective but are in some cases wrong and confusing. I recommend it non the less until I find (or create) something better. share quote
 10 October 2012 receptor Veteran   portfolio Emil Assarsson Malmö, SE Originally Posted by DanielBrown: -Locating vanishing points, how do we know where they go? One, two and 3 point systems. Trying to locate the 3rd vanishing point is rather tricky because it moves. This drove me nuts. The closer the object is to the horizon, the more vertical the objects and the farther the 3rd vp gets from the horizon. The 3rd vp will never move. It will behave just like all other vp's. It does not depend on the objects location relative to the horizon. It depends on the papers location and tilt. I have to assume that we work on a flat surface. Originally Posted by DanielBrown: -How to actualy draw a square, and a cube. This is my simplest explanation, it explains the location of the 3rd vanishing point, drawing a square and a cube: http://reflective-sentinal.devianta...-cube-329293520 I can't find any proof in this method and I'm finding it strange. Originally Posted by DanielBrown: -Assuming my diagram is correct (which it certainly might not be, or I may be interperating it incorectly), why there is twice the angular distance verticaly than there is horizonataly. I don't know that it matters, but it .. bugs me. I probably have something wrong here somewhere: http://reflective-sentinal.deviantart.com/#/d5g7tg3 i find this diagram even stranger... I guess you are trying to figure out how to make a projection that reflects the eye? If you try my method you will find that there is openings to make projections to a curved surface. Out of scope for me. Originally Posted by DanielBrown: More complicated stuff: -First example: Two 6 sided dice on a table, rotated randomly. The vanishing points on the horizon move according to plan view, while the z axis remains shared. We can compare the size of the dice by looking at the z axis, and transfering the scale measurement between the dice like a 1 point perspective system. Try to use my projection method and then try find shortcuts for your needs. It's not that complicated. Originally Posted by DanielBrown: -Second example: Take the same two dice and roll them. As the dice tumble through the air, none of the axes line up, making it rather hard to compare locations of vanishing points or compare sizes of the cubes. I don't have a way to simplify this one.... probably one of those things to throw into a 3d program for practicality, but there should be an answer somewhere. Use two semi-transparent papers. It is possible to let the cubes share the z-axis during the construction and then rotate to paper around the eye-center point for one of the cubes. share quote
 10 October 2012 Quadart It’s the journey…   portfolio Bill Melvin freelance cg artist USA It seems like you guys are trying to reinvent the wheel here. Established linear perspective techniques have been distilled, through the centuries, down to a very efficient ‘science’. Most everything you need to know about linear perspective drawing can be found here (also located above in the Art Tutorial… sticky): http://handprint.com/HP/WCL/tech10.html#top I prefer starting out object construction using this method: …opposed to either one of you two guy’s alternative methods, which seem a bit confusing, atm. __________________ PORTFOLIO SKETCHBOOK ZBrush Stuff share quote
 10 October 2012 receptor Veteran   portfolio Emil Assarsson Malmö, SE Hurmm, either I have failed to explain my method correctly or you have not read it :-( If I reinvent the wheel we have been using a square formed wheel until now. I know my method is correct and I understand it perfectly. The method you are using is overly simplified and actually incorrect in some areas. It tries to give the reader a step-by-step method and it doesn't learn you anything about what really happens. You just end up with an OK result. If you try to add a 3rd VP to it it will fail miserably. share quote
 10 October 2012 receptor Veteran   portfolio Emil Assarsson Malmö, SE This is how the method can be used to reverse an image of a cube created with Blender. The camera lens was 35mm and sensor size 32x18mm. https://docs.google.com/file/d/0B9r...VhoMGsyWG8/edit Image: https://docs.google.com/file/d/0B9r...TMxOEpnU2M/edit share quote
 10 October 2012 receptor Veteran   portfolio Emil Assarsson Malmö, SE DanielBrown: Sorry, I can't make sens of the methods you are using. It would be of great help if you clarify how the logic of this really works. I need to see how you'r setting the distance between the eye, paper and object. Start a separate threads about the different problems you are dealing with. This is getting confusing and I'm feeling sorry for the other readers as well as me :-P share quote
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