Radius changes over distance

To begin, this is my first post in the forum, please bear with.

I’m attempting to model a swimming pool interior accurately. This involves changes in radius. For instance, the vertical corners in the deep end of the pool are effectively 90 degrees at the waterline, but change to a 12" radius at the bottom, where they meet the 12" radii between the walls and floor. In the shallow end, the radii between floor and walls will typically be 3" to 4", on steps around 2". Compound all of these changing radii with a non-linear pool shape and you wind up with one very frustrated pool designer. I’ve used Fredo Roundcorner, but I’ve not figured how to, or indeed even it can be configured to change radius over distance.

For simple rectangular pools I’ve used solids to intersect shapes, but for curvilinear pools this gets - complicated. In addition to all of this, I would like to use the model to accurately calculate pool volume, meaning the model must be “clean”.

I’ve included a model of a currently in-production pool.

Any help is truly appreciated.

An option might be to use Fredo6’s Curviloft and/or Extrude Tools by TIG. Both are from Sketchucation.

Before you add anu more geometry to your model I would suggest fixing what you have. Correct the face orientation so you have no exposed blue back faces. Using a style that has the same color set for both front and back faces is not a fix for this.

I cleaned up your component by fixing the incorrect face orientation. I also eliminated stray edges, missing faces, and internal faces to make it a solid component. That just makes the thing easier to work with.

Nexted, I copied out the bottom of the pool and laid an inner curve representing the limits of the radii on the bottom of the pool. I just used a level edge based on the flat shape of the pool for the top limits. You could set those out anyway you need. Then I added curves at various locations around the pool and used Extrude Edged by Rails from TIG’s Extrusion Tools. I didn’t go all the way around obviously and I did not try to hit exact radii for this example.


I see that I’ve some learning to do. I’ve been using Sketchup for years, yet this is the first time I’ve been faced ((no pun)well, some pun) with the rationale for the different face colors. #facepalm.

This is gonna be a stunningly beginner question (I imagine there’ll be a few of these) - how did you do that?

How did I do what? Fix the face orientation? In your model it was a bit of a challenge because of the way you built the pool geometry. I started by changing the style so the back faces are evident. Then I tried right clicking on one of the correctly oriented faces to use Orient Faces but that just made things worse in your model. So, I selected all of the pool geometry, right clicked on it, and chose Intersect Faces>With Selection. Then with Hidden Geometry made visible I started selecting exposed back faces, right clicking on them and choosing Reverse Faces.

While I was cleaning up the pool geometry I deleted all f the coplanar edges to reduce the number of edges and faces in it. I eliminated stray edges, internal faces, and holes in surfaces to make the thing a solid component. I would urge you to work at keeping components and groups solid. They will be cleaner and easier to work with as you continue.

Face orientation ends up being important in a number of aspects of modeling. Texturing is more straightforward with correct face orientation. The results of tools like Push/Pull are impacted by which side of a face you are clicking on. Many renderers won’t render exposed back faces even if they have textures on them, And if you ever want to make physical models using 3D printing, face orientation is important. It tells the slicer software which side of the face is supposed to be ambient air and which side is the print media.

Apologies, I often forget that folks can’t just see my thoughts without a bit of communication.

  1. How did you fix the incorrect face orientation?
  2. I spent a LOT of time fussing with stray edges - the design process of this pool was heavily iterative, more so than usual, which for me means lots of stray bits. That you found more seems a good indication that I was unsuccessful in cleaning up. What is your method for hunting these down?
  3. I had attempted to remove a handful of internal geometry but was unsuccessful - removal of internal faces and planes would result in changes to visible geometry. Any pointers?

As I’d indicated before, I’ve used Sketchup for years, since it was a Google product. The huge majority of that time was spent modeling simple cubic forms or simply curved forms, without any need for rendering or any further functionality beyond a picture with dimensions. At this point I’m quite familiar (I think…) with the toolsets I commonly utilize and keyboard shortcuts, but any suggestions for additional training would be appreciated.

Hopefully I explained that in my edited reply, above.

A lot of it is just poking around. Looking at the model in X-ray helps. Turning on hidden geometry also helps.

Intersecting faces helps with that. Also note that weird floating interior faces and holes in surfaces will be shown with Profile edges. So looking for thick edges inside the object helps.

If I were modeling that pool from scratch I think I would probably have split it up into smaller objects so they could be manipulated independently of the other elements.

As for more training, it might not hurt to go through the SketchUp instructional materials at learn.sketchup.com as well as the various Square One videos on the SketchUp YouTube channel. Unfortunately I don’t know of any tutorials on modeling pools in SketchUp but really the things you model are really all just a bunch of geometry.

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Thank you very, very much for your thoroughness and patience!