<p>If I want to draw a grid on the ground in one point perspective, do I always have to guess the placement of the second horizontal line?</p>
<p>I know I can make future lines proportionate with the previous ones by drawing diagonal guidelines, but is there any way to determine how far apart to place to the second line?</p>
<p>Or if I'm say drawing a house in 1 point perspective, do I have to guess how far back to place the back edges?</p>

CC BY-SA 4.0
2023-10-02T16:36:48.607Z
Perspective drawing is based on measurements and math. So its not really clear why you are guessing at anything.
rebusB
CC BY-SA 4.0
2023-10-08T13:27:08.737Z
@rebusB Then how do I figure out where to place the second horizontal line?
stackers
CC BY-SA 4.0
2023-10-09T17:03:47.170Z
Sorry, that was a general response. What I meant to say is that it is not clear what you mean by second horizontal line. Whatever it may be perspective drawing is not arbitrary, so the location would be based on the object's proportions relative to the area of the drawing and the eye-height of your horizon ie. not a guess.
rebusB
CC BY-SA 4.0
2024-03-18T06:36:49.893Z
All lines going in the same direction in real life meet at same point in image plane, or at a so called point at infinity which in effect means they never meet. If you want horisontal lines spaced evenly in real life maybe you could try drawing V shaped diagonals from corners of image or the two cornerpoints of horizon? Not entirely sure if that would make them square though. Otherwise maybe  trigonometry or the homography matrix.
Emil
<drawing><linear-perspective>
Do you always have to guess the first line when drawing in perspective?
stackers
# Do you always have to guess the first line when drawing in perspective?

(Asked by: username_0 on 2023-09-25)

If I want to draw a grid on the ground in one point perspective, do I always have to guess the placement of the second horizontal line?

I know I can make future lines proportionate with the previous ones by drawing diagonal guidelines, but is there any way to determine how far apart to place to the second line?

Or if I'm say drawing a house in 1 point perspective, do I have to guess how far back to place the back edges?

**Tags:** drawing, linear-perspective

> **Comments:**
> **username_1**: Perspective drawing is based on measurements and math. So its not really clear why you are guessing at anything.  
> **username_0**: @username_1 Then how do I figure out where to place the second horizontal line?  
> **username_1**: Sorry, that was a general response. What I meant to say is that it is not clear what you mean by second horizontal line. Whatever it may be perspective drawing is not arbitrary, so the location would be based on the object's proportions relative to the area of the drawing and the eye-height of your horizon ie. not a guess.  
> **username_2**: All lines going in the same direction in real life meet at same point in image plane, or at a so called point at infinity which in effect means they never meet. If you want horisontal lines spaced evenly in real life maybe you could try drawing V shaped diagonals from corners of image or the two cornerpoints of horizon? Not entirely sure if that would make them square though. Otherwise maybe  trigonometry or the homography matrix.  

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## 0 answers

