Visualize a turned cylinder from a segmented rectangular blank


#1

Hi all,

I’m trying to figure out if there is a way to visualize how something is going to look after it is turned. I know there are some threads on this, but not exactly what I’m thinking about. I want to start with a rectangular blank, segmented. So lets say I’m using a 4x4x12 block of holly. I cut a 2x2x2 section out and glue in a piece that is died black. I want to know how the black section is going to appear after it has been turned. Is there a way that I can create the original blank and then pair it down to a cylinder that will show the final appearance?


#2

There are no actual solids in SU, only surfaces. So you can’t “pre-color” a surface that hasn’t been defined yet by coloring the solid material from which it is subsequently made. There are no solid materials.

In general, the sequence of operations in SU is 1) construct geometry and 2) apply materials.

This is not to say that you can’t paint the black section after the fact to achieve the desired effect, even if you can’t exactly visualize it beforehand.

-Gully


#3

From your question, it’s not really clear to me how you are insetting the 2x2x2 block into the 4x4x12 block. However, if you create the 4x4x12 block as a group and then the 2x2x2 block as a separate group, you can then intersect a cylinder with the 2x2x2 block and see the effect:





A different example:



#4

It’s very easy to set up a lathe in SU and paint the segments to suit.
Use follow me to make your shape, turn on hidden geometry and colour your wood to see what you get.


#5

Wow! A lot of good stuff here. I didn’t expect nearly as quick a response as I got. Thanks. I misspoke on the inset dimensions it should have been 2" deep, 2" tall and 4" wide, but I think the concept is the same. The inset would be flush with all sides, so basically a dado with a piece glued in. Is the process still the same?


#6

Great concept. I’ll have to try that.


#7

Another possible approach would be to draw the pieces you plan to glue up and intersect them with a turned shape. Then delete the waste. If you have SU Pro, you can make very quick work of it with the Solid tools. I did this as an example for a guy who wanted to see how a bowl would look if it was made from stacked laminations that were glued up with each layer slightly rotated.
Laminations

In this case, each “piece of wood” is a separate component.

Laminations


#8

Wow, that is way awesome, DaveR.


#9

Thank you, Rick. Somewhere I have a better example but I can’t find it.


#10

One way to accomplish what you want is to build a segmented blank piece by piece, as you would in the shop. Make each segment a component. Then Intersect those blanks with a component that is the shape of the finished bowl or vessel. Once you erase all the waste, you’ll be left with a vessel showing the seams between segments. Then you use the Paint Bucket tool to apply color to the segments.
That’s the short answer. For the longer answer, you’ll have to wait until my article on this subject appears in “American Woodturner,” the journal of the American Association of Woodturners; it’s scheduled to appear sometime in 2016.
Best,
dh


#11

Yes:

Your topic indicates that you are asking about a cylinder, but if you use a profile and the Follow Me tool (as shown by Box), you can use the same steps for any turned shape:

I had to add four short lines in the corners of the resultant intersection, but once I did so, clicking on the inset showed that it was now a separate bounded surface:


#12

Jim (and everyone) thanks.

My head’s spinning with all the help. These are all great ideas. I tried Jim’s and it works great, seems pretty simple and repeatable. Since I’m still somewhat new to sketchup this seems like it will work best, but I’m interested to try some of the other ideas.

David, I have seen a tutorial similar to what you’re describing and it looked really cool, just wasn’t exactly what I was looking for. I will look forward to your article!

Dave R, your idea is awesome (if a little overwhelming. Do you have a tutorial on how to do it? I’d love to take a look at it. Always looking for new options.

Thanks so much to everyone.

While I have you all here, what I’m basically trying to do is create a beer tap handle shaped like a beer bottle that will appear to have labels on it. I am coming up against a difficulty this morning in shaping the neck of the bottle. I feel like there is a way to simply reduce the top of the cylinder to form a “cone” or the neck, but can’t remember/figure out how. Any thoughts on that?


#13

Find a beer bottle image on the web (or use your own) and trace over it. Make it into a profile and then use the steps above to intersect the 2x2x4 block.


#14

I guess I did a private, online tutorial for the guy who asked for help on it. Never did make a proper tutorial, though.


#15

Thanks again, I’ll try that.


#16

Hi, Your article is is the help I an looking for to visualize what a bowl from a board will look like before assembly. Would hate to wait up to a year for my copy of the American Woodturner. Is there any way to purchase the article now? If you want you can respond directly to me at mholowach@yahoo.com.
Thanks
Mike


#17

Dear mholowach,
I’m sorry to say that I can’t jump the gun on the article. However, the other posts in this thread give you plenty of information and advice on how to preview a turned shape. You won’t go wrong if you use their advice.
Best,
dh