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Need a bit of help with Art(:sad

  1. Sep 27, 2006 #1
    Need a bit of help with Art(:sad:)

    (Okay, if this isn't in the right location, feel free to move it and inform me.)

    I'm doing a 1-point perspective drawing on a 18x12 inch piece of paper. My vanishing point is directly at (9,6) and my back wall is 1.5 inches left and right, and 1 point up and down. I made marks every 3 inches along the bottom, and connected them to the center(dotted lines past the 7 inch point, which is where the bottom floor meets the back)

    Now, what I am trying to do is, I am trying to make a floor that is made of 6 by 6 tiles. How would I make it in perspective, yet make it seem evenly spaced? (Is there/what is the ratio of distance between the tile edges as it decreases over a distance of 5 inches?)

    Thank you in advance!
    (P.S. Clarification given on request :tongue2:)
  2. jcsd
  3. Sep 27, 2006 #2
    Hmmmm. Yes. I know exactly what you're asking, but my brain won't lock onto the answer. I believe there's a simple formula. It's the same way you generate the spacing when you shade a cylinder by means of incrementally closer spaced lines as you approach the edges.
  4. Sep 27, 2006 #3
    I believe that if you draw a line from the front corners of your tile through the center of the back edge to where it intersects the line of your side edges to the vanishing point you get the back edge of the next tile.
  5. Sep 27, 2006 #4
    Here, I think this explains how to do it:


    From the first paragraph:

  6. Sep 27, 2006 #5
    is that what I said?
  7. Sep 27, 2006 #6
    Well, let's have another look at what you said:

    So, yes, more or less.
  8. Sep 28, 2006 #7

    I'm sorry, but I'm probably not getting it; How do I know how big to make my first row of tiles? (I'm horrid at visualizing, due to a lack of practice :grumpy:)

    Since the 6x6 tiles have to cover an area much, much wider than they are wide, I'm going to have to use rectangular tiles to keep it even.

    But still, at least, how tall do I make my first row of tiles?
  9. Sep 28, 2006 #8
    The diagonals sort that out for you: no calculations necessary.

    What you're trying to do is exactly like the illustration at the link I posted with one difference. The tiles at the link are 7 across x 6 deep. If your drawing has one less line radiating from the vanishing point that automatically reduces it to your 6 x 6 tiles.

    You start by drawing a horizontal line through the vanishing point. Then mark off two points on that horizontal evenly spaced on each side of the vanishing point. Draw diagonals from those two points to the outer edges of the floor at the front (bottom) of the paper.

    Where those diagonals intersect the original radial lines you draw horizontals. These are automatically spaced at the proper incrementally increasing distance from each other to appear "right" to the eye.
  10. Sep 28, 2006 #9
    Oh! I get it!

    Thank you. :rofl:

    EDIT: My two end "distance" points are off the page... is this normal? :S

    (Basing it on how far the illustration is. Are the placements arbitary?)
    Last edited: Sep 28, 2006
  11. Sep 28, 2006 #10
    You're welcome, sir.

    I've never actually done it myself, but it looks to me that the more of your page that is taken up by the floor the more likely you are to have reference points off the page.
    I can't tell without doing it. You have stipulated the location of your vanishing point but not the distance of the back wall from the front of the paper. It could be you have a range that will work, or it could be there is only one distance that will work.

    Realize, too, that if you have a t-square or any means of easily striking horizontal lines you don't really need two diagonals. A horizontal from any point the diagonals intersect the radial lines will intersect them automatically where the "mirror" diagonal would intersect them.

    The diagonal has, in any event, to create a situation where the first row in front of the back wall is the thinnest of all, with the rest getting incrementally thicker as you approach the bottom of the page.
  12. Sep 28, 2006 #11
    It all depends on the perspective you want to give. As a matter of fact, to be truly realistic-looking, your schematic needs to have a slight fisheye effect, relative to the distance between the point of view and object.
    Imagine your field of view as a square pyramid of infinite height, the apex of which is your point of view. You are trying to project a view looking from the apex to the center of the "base". As different points along the straight lines formed by 3D objects are at a varying distance from the apex, they will not project on a 2D plane as straight lines. This is the fisheye effect.
    It does not matter whether some point falls on the page or not, as it is simply a matter of the FOV you chose.
    Last edited: Sep 28, 2006
  13. Oct 1, 2006 #12
    Three days since we've heard from Blahness.

    Blahness, how'd your thing turn out?
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