QUESTION: "I am creating a shape in Sketchup and made an arc along one of the edges of a rectangle. The height along the edge is 0.05m tall, and the radius of the arc is 0.01m. I would like to create an arc on the other edge as well so I assume I'll need to create a diagonal arc in the corner of the rectangle. How do I maintain the 0.05 to 0.01 arc dimensions along the sides when making the corner arc? What will its radius need to be?"

I donít have the screenshot on my phone so I can't attach it again now. But by corner arc I mean it bows inward like along the edges. Set 45 degrees offset from the arc on one of the edges. I set a corner arc to 0.05 height and 0.01 radius and found the edge radius was closer to 0.007200. How do I make the edges radius equal 0.1?

If you need more clarification please just reply instead of reject. That way I don't need to copy and paste everything from the previous question.

ANSWER: Hi James,

I am still unable to visualize the shape you are describing.  You have made an arc along one of the edges of the rectangle.  If you wish to do the same on another edge, I fail to see why this would require the creation of another arc on the corner.  I also do not understand how you make an arc out of a corner, instead of an edge.

If you can attach a screenshot with some arcs roughly drawn in to show your objective, I'll see if I can help you find the exact parameters.


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QUESTION: Basically although a rectangle and not a sphere I want it to look like an apple core. I am designing the mortar portion of brick patten where it goes in a little on all sides. From an aerial view the bottom edge would have an arc line that is vertical and the concave side faces town. On the right side edge the arc would be verical from aerial view and concave part of arc facing right. The corner arc would be top/left to bottom/right from aerial view concave facing bottom/right.

Hi James,

The apple core helps me to visualize.  If I am understanding this correctly, both the radius and the center of the arc are important.  You should be able to retain the 0.01 radius for the corner arc, provided you center the arc far enough away.  How much of the corner the arc you want the arc to "eat" also plays a factor in this.  If you want to save most of the corner, you can either use a distant center or a very small radius (in the neighbourhood of the 0.007200 you mentioned above).

Hope this helps,


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Azeem Hussain


I welcome your questions on algebra, 2D and 3D geometry, parabolic functions and conic sections, and any other mathematical queries you may have.


4 years as a drop-in and by-appointment tutor at Champlain College. Private tutor for dozens of clients over the past 8 years.

CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry

Bachelor of Science, Major Mathematics and Major Economics, McGill University, 2014. Diploma of Collegiate Studies; Pure and Applied Science, Champlain College Saint-Lambert, 2010.

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