Sink Design


Hi All. I am trying to construct a sink for a project and I have a question about sink corners when one or more sides are at different angles from the norm. In my sink, I have the two sides and the back vertical and the front at a 30 deg. outward angle, As well, the two sides are at a 22.5 deg. angle (like the sinks in Harry Potter’s Chamber of Secrets.) Are there plug-ins or free extensions that can help in making this happen?

Any replies should be directed to me at




That sounds like a contradiction: how are the sides simultaneously vertical and at a 22.5 deg angle? Please clarify…


Hi Steve,

If you were to view the model from the top, the two sides are vertical, and you would only see the tops, and the front would be wider that the back, with them both going to a center. As for the front of this model, if you were to see it from either side, the top of the front face would be out at 30 deg. from the vertical. I have a jpg file of the one in Chamber of Secrets that is inclided for you to look at.




Making the geometry of that shape is very straightforward. It is a section of an octagon. Then copy the face to the depth you want at cut it at the 30 deg mark.
Join the corners and you have a flat sided block in the shape you describe.
It’s down to you then to fashion that into the sink shape you want.


Thanks, Box for your input to this endeavour. I have had the basics done already; the problem I’ve got is with the corners, I would like all the corners rounded as in the one in one in the Chamber of Secrets sink, with a lip around the top, and rounded corners at all four corners and around the bottom. Do you or any of your fellow sketchers know how to do this, or suggest a plug-in or extension that can do that part of the project?




You can search for FredoCorner.


I was reproducing your technique and tried creating the guide line with the measure tool. The guideline created didn’t show an intersection with the lower surface, so I couldn’t accurately draw a line on the lower surface.

When I used the protractor, the guideline then showed an intersection with the lower surface so I could draw an accurate line there.

What am I missing?


Perhaps you are missing the fact I also used the protractor not the measure. Or to put it another way, you aren’t missing anything.


I regrettably have used guidelines very little over the years - the measure tool won’t indicate an intersection with a surface, but the protractor will?


I think it’s me that’s missing something this time, I’m not quite following what problem you are having. I meant the protractor way easiest for setting guides at angles.
Here you see two guides both created with the tape measure showing the intersection point at an angle with a face. Could you elaborate or show me an example so I can understand better.


I reproduced your process except I used the measure tool to create a guide. At the point where the guide intersected the lower surface, the pencil tool could not find an intersection point.


How are you creating the guide? Straight then rotate or …?


I create a vertical guide off the top surface, from the same point as yours (with the measure tool). I then rotate it 30 deg. and copy the surface down - I have reproduced it again, and there is no intersection for the pencil to find.
I’m not using the measure tool to pull a guide parallel to an edge, or create a point at a fixed distance - I think I triple click to create the guide?

Yes - when I click on the guideline now - it is described as a point, not a guideline.


The tail of a point isn’t a guide so it won’t intersect with anything, it is just an indicator that there is a point there somewhere.
So use a guide pulled from an edge, or the protractor.


The evidence…



The evidence screen-capture shows a guide point. SketchUp’s inference engine does not detect intersections of the finite-length tail of a guide point with other entities. What @Box is using and suggesting is to use a guide line (which can be created with both the Tape Measure and the Protractor tools). A guide line is an infinitely-long entity, with which SketchUp’s inference engine does compute intersections.


Yes - it is evidence I didn’t know what I was doing.