# Vanishing Point: Rotating Grids, Maintaining Size

Posted by on May 9, 2014 in Perspective | No Comments

There are lots of ways to solve any perspective problem.  With this question, I wanted a good solid no-frills way to solve the problem on the fly.  And a solution that could be applied to a lot of other problems (opening doors, etc.)

Dear Jason,

Thank you for writing “Vanishing Points”. It is the best book on perspective drawing I have come across and it has made a great difference in my work.

I have a question about rotating grids and hope you can help me with it. On page 37 of your book I understand how you rotated the grid, and I have been able to replicate it so that my second grid has the same dimensions/tile sizes as the first. Where I struggle a bit is on page 39, point 3. I understand how to add new vanishing points by rotating my triangle any angle. However, when I rotate my new grid any arbitrary angle, how do I end up with tile sizes that have the same proportions as those in my first grid? Do you use the first grid to count how many tiles the new grid lines have gone over to determine the new tile width or is there another way? My thanks in advance.

Kind regards,

A.

Hey A.

Thanks for the question

Okay, so there are highly technical ways using a measuring point and a scale, but here’s a good, solid intuitive say to do it.  Counting grid lines will probably mess you up, since squares aren’t the same width from different angles.

But a circle is the same width from any angle.  So inscribe a circle into your grid.   Which on the page means drawing an ellipse. It’s best if the square you’re inscribing it into is near the vertical center of the page.  If it’s off to one side, it’ll be hard to get it to line up accurately.   You can drop in a long and short axis if you want (which in this case are a horizontal and veritcal line), or just freehand it from the edges of the grid square.  You only need a moderately good ellipse to get a good result.  Or course, if you’re doing this in the computer, you can just use the ellipse tool.

Hope this works for you, let me know if you have any questions.

-j