# Drawing the Ends of Grooves that Do Not Reach an Edge

I need to draw some stopped grooves. The ends must be quarter spheres of negative space, just as the grooves are negative space. I figured out how to draw the groove but cannot get the groove ends. I’ve tried used the Follow Me Tool with no good result.

Could someone point me to a how-to, tutorial, KB article or post where this issue has been addressed?

TIA

Stopped only at one end or both ends?

Did you draw the half circle on top of the surface ? It can act as the profile.

Then you’d have a Follow Me path perpendicular to that, which is a quarter circle. (You could even copy the half circle, cut it in half, then rotate the result.)

Basically, you create a segment of a sphere and intersect it at the ends of the groove.

Also see the Shapes plugin from the SketchUp Team:
http://extensions.sketchup.com/en/content/shapes

Thanks for the replies!!!

Alas, they only lead me to more questions.

First, I need to make grooves that are stopped at both ends. I would like to know how to make both quarter sphere (half hemisphere) and ramped ends that extend from groove bottoms to the surface from which the grooves are made.

I experimented with the Follow Me Tool but could not get it to do what I need. I’m certain that I have some conceptual blocks that are giving me trouble.

I tried to draw a ball or sphere and did so successfully, but it is a representation of positive space and what I need is its opposite, negative space. I found a post about using reverse faces but have been unable to grasp the concept well enough to use it.

Yes, I have the half circle at the end of the grooves and it rests on the face from which the grooves are formed. I created the grooves by drawing a 2 dimensional rectangle then making an arc on the end of it to the depth I want then using the Follow Me Tool to extend the groove. I then drew an extension of grove and placed a half circle on it. I cannot see how to turn that half circle into what I need. If it helps any, my approach was to draw the rectangle 1/2" wide. I then create and arc with radius of 5/16". The half circle has a radius of 1/4".

As for shapes, I don’t seem to have any in SketchUp 2016 Make V.16.1.1449 64 bit. Looking under Draw > Shapes I see Rectangle, Rotated Rectangle, Circle and Polygon but none of the other shapes mentioned above. I followed the link you gave me, Dan, and read the blurb that said to install from within SU. I followed that process and can even see the su_shapes extension in the Window > Preferences > Extensions panel, but I cannot select it. Does that mean it only works in Pro? If not, what else do I need to know to install it?

Again, thank you all for the replies!

rh

Here’s one way. Maybe with a picture it’ll help.

From the left:

1: Draw a positive shape that you can use as a cutter. In this case half of the section as a profile and a circle for the Follow Me path.
2. Run Follow Me to create the shape. I used a circle for the path instead of a semi-circle because it’ll be easier to clean up the waste later.
3. Place the cutter shape on the "board getting the groove.
4. Select the surface of the cutter and the face on the board, right click and choose Intersect Faces>With Selection.
5. Delete the unneeded geometry of the cutter.
6. Delete the face skinning the groove and correct the face orientation as needed.

As for the cutting shape, it might be easier to think about the volume of space the cutter would pass through to make the groove and draw that. The exact method for drawing that shape will vary depending on the shape.

Since SU is a surface modeler, there is no solid material to mark the “inside” of an object and distinguish it from the outside; the only difference between inside and outside–positive space and negative space–is which side of a surface you’re looking at. If you’re looking at a positive space and you want to be looking at its figure-ground alternate, just turn it around, or invert it. The rest is just a question of context and perception.

So to make a half-circular blind groove in a face, just make a tube with rounded ends, remove half of it, and then just place it into the face, removing the round-ended rectangular face that covers the groove. Like this:

Hmmm…just like Dave’s.

-Gully

Thank you, Dave and Gully!!!

Those suggestions allowed me to break through my conceptual barrier. I followed your instructions and created a tube but my ends were faces, not hemispheres. I drew a half circle arc across the diameter of one end then selected the tube face and clicked on the Follow Me Tool. To my surprise, I lost the tube but got 2 hemispheres, one at each end where the tube had been. I then bisected the hemisphere giving a quarter of a circle. I deleted the line across the diameter and, lo and behold, there was a groove end as pretty as you please.

So many ways to skin a cat!

Thank you, both, for the kind assistance.

Here’s another way to skin your cat.

If you happen to fall on a cat while holding a knife in such a way that the cat’s skin somehow comes off in the process, I don’t know if that really counts as skinning the cat. For full credit, I think it has to happen essentially in the manner intended.

-Gully

Incidentally, my apologies to any cat lovers who may feel offended by the graphic nature of this metaphor. I can assure you that no cats were harmed in the writing of this post.

Especially not tigers, right?

Simple and elegant.

Thank you, Box!!!

What is that last tool you used, Box? It shows as an ‘X’ in a circle in your vid.

He might be asleep so I’ll take the liberty. It’s the Erase tool. It’s found in the Standard toolbar. It’s the equivalent of hitting the Delete key but it makes it easier to show what is being done in the GIFs.

Thanks, DaveR!!!

Your post led me to explore the toolbar options more thoroughly. There are some neat things there that I didn’t know about. I added the Standard toolbar (would have thought that something of that name would be a default) and a couple of others.

I tried using the Erase tool and got a slightly different result. After using it Box showed that the drawing did in fact show a groove. Mine just erased the face where the half tube protrusion had been. What did I do wrong?

Did you get and then select the domed surface (shown with reversed face in his GIF) before hitting Erase or the Delete key?

There are a number of toolbars that you might want to have out and you might want to make some custom toolbars. SketchUp gives users the ability to show the tools thy want to show. They aren’t forcing it on anyone.

It’s good to know that I can customize toolbars. I’ll give that a try sometime.

I made a drawing with multiple grooves to see if the technique could be used on more than one at a time. I discovered that the Follow Me Tool doesn’t allow you to select multiple objects. OK. Lesson learned. I then tried Box’ method with the results you see below. The 2 at left worked OK. The third one removed the face. I don’t know how I created the 4th one, but I didn’t try to make it a groove.

For some reason, my screenshot doesn’t show the face removed on the 3rd groove from left.

How did you draw the thing you’re trying to put the grooves in? Why are the faces reversed and why are there lines on the surface?

Instead of drawing four of those shapes with four Follow Me operations, why not just draw one and use Move/Copy to copy it the required number of times.

Did you try the method I showed?

The drawing was just me trying to learn something. I have in mind a fluted column face. I was tinkering with proportions that led me to draw the lines. After doing the 2D layout, I decided to try the grooving technique Box used. What you see is the result of my noodling.

Yes, I tried your technique too and it worked.