Bending cylinders using Follow Me - face corrupted on tight arcs


#1

Hi,

I’ve been using the Follow Me tool to extrude a cylinder along a curved path. However, the design I’m working on required some tight bends (around 50 degree angles) and when I extrude the cylinder along this part of my path, it leaves unconnected parts of the face. I can see that this is a result of the tight angle, but was wondering if there’s a way of patching up these holes? I’ve tried using the soften/smooth options, but it hasn’t resolved the issue. Screen grab of the bend in question below - also attached the .skp file in case there’s something else I’m doing wrong that could prevent the issue occurring in the first instance.

Many thanks in advance, Will

W_bench_early.skp (168.6 KB)


#2

This is due to the small size of the faces you are asking SketchUp to create. Work at a larger scale or use the Dave Method. Search for that here. Box has done a couple of nice GIFs that show how it works.

It’s also worth noting that the radius of the bend is smaller than the radius of the tube. You’ll need to modify that bend to make it work correctly.

Larger radius:


#3

This is a well documented issue.
SketchUp’s in-built tolerance is 1/1000"
Any points closer than that are assume to be coincident.
Therefore SketchUp doesn’t create the edge from those points, and the face relying on that edge is therefore not made.

If you View your new form with Hidden Geometry ON and select one of the edges around the ‘hole’ you’ll see the tiny dimension.

If you are making small objects you can sidestep the limitations by making the object a component.
Then make a copy of the component off to one side.
Select that and Scale it up by x100 [leaving the original as it was].
Now edit the enlarged copy.
Zoom as needed to see what you are doing !
Do the FollowMe and the surfaces should now form as hoped…
Exit the edit and erase the enlarged copy.
Go back to the original instance.
It will reflect the changes made to the enlarged temporary version.
Select and Explode it as desired…

Tiny geometry can exist, but it cannot be created directly.


#4

@DaveR I will look into the Dave Method now, sounds exciting! Thank you for the additional context explaining why the issue emerged in the first place - very useful information.

@TIG This is also really interesting - I suppose there’s nothing stopping me from creating all my models at x100 from the get go, then just shirinking back to x1 when adding all the dimensions when complete.


#5

I effectively outlined the ‘DaveR’ method…
He posted just before me !

I recommend his method…


#6

I used the Dave Method, too. :wink:

The original is shown selected and the copy I worked on is in the background.


#7

I’ve had really good results using this technique, thanks so much for your help guys!


#8

The Dave method comes in a tradition of great artists and craftsmen:


#9

For follow me to work correctly, the radius of the path must be bigger than radius of the profile. Errors will appear even when the radiuses are the same. This is common for all 3D modelling applications. Plugins like Fredo’s RoundCorner can overcome this as they use their own methods to build the tight parts.


#10

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