I will be using a Sketchup plugin named Curvilot to “Create loft junctions following a given path

Take a look at the drawing to the left. You are looking at it from a side view. There are three items of interest here .. a circle representing the #228 dia at either end of a curve .. or path that the plugin will loft along .. create a shape from one end to the other along that path.

This is an interesting plugin. You could have a square at one end and a circle at the other and the tool would create an “elbow” connecting these two shapes.

It is both as simple as that .. and more complicated.

Here Curviloft has been applied to he above. I am showing the surface generated by the plugin between the two faces along the path. I traced and colored a couple of polygons to highlight them .. and indicate “Top Most line” .. that bit is the “important thing”.

This is a 60 sided circle. You can think of a square as a 4 sided circle or a hexagon as a 6 sided circle. The point being that if we want to attach the flange we created earlier then we need to match the number of sides in the circle (60). that the dia is exactly the same (6.3 in this case) and that the top most line indicated in the drawing aligns with the Top Most line on the flange mesh. That way.. all of the polygons link together seamlessly.

.. or .. you can cheat a bit as I describe next …

Cheating or Smart?

SO … I have the curved line .. my path in place and now I have slid two of the flange pieces I created in the British O Scale Flanged Pipe article earlier shown in purple.

The ends of the path are touching the face of the two flange assemblies (figure ‘flange assemblies’ is as good a name as any).

The path then is a curved path .. the center of the elbow to be created between the two flanges.

The two Cyan flange assemblies are aligned with the axis of each of the Purple flange assemblies so they can be slid into place once the elbow is created.

Deleting to Create the ‘Bits’

Remember .. .what we want is to “Create loft junctions following a given path” .. which means a starting shape, an ending shape and a path to loft along (create the mesh).

I deleted all of the Purple flange assemblies except for the faces even with the ends of the path. These will be the shapes .. shown in red to make that mesh down the length of the path.


At this point I have completed the loft and the mesh has been created between the two faces (red). There is some cleanup to do .. you have to run the plugin twice for the inner and outer faces then explode.

This gets it ready for the next step which will be to slide the flange assemblies in place.


Time to “Assemble” the flange assemblies to the lofted elbow.

This is where you need to use a combination of the arrow keys and the mouse to constrain the movement of the flange assemblies. They are still grouped at this time which makes this relatively easy to do.

The right side flange assembly is slid along, constrained on the X axis until it snugs against the end of the elbow (hold down the RIGHT arrow to constrain to the X axis).

In the same manner the lower flange assembly is slid up, constrained on the Y axis until it also fits snug against the elbow (press and hold down the UP arrow).


The model is completely ungrouped, then everything is selected and intersected. I then sectional viewed the model to remove internal walls. Finally, I ran a couple of plugins to clean up the mesh .. Solid Inspector² and Cleanup³.

The mesh may be ‘complete’ but to print at Shapeways in multiple pieces it needs to be put on a sprue .. but .. consider it ‘ready’ for such an operation at this time.


Finally a sectional view for no other reason than .. “I could” and it is interesting to see a bit of the internal makeup of the “British O Scale” Flanged 10″ elbow

Leave a Reply

Your email address will not be published. Required fields are marked *

The maximum upload file size: 100 MB.
You can upload: image, audio, video, document, spreadsheet, interactive, other.
Links to YouTube, Facebook, Twitter and other services inserted in the comment text will be automatically embedded.