I'm struggling with this seemingly simple problem in my own CAD program, so I'm wondering if it's possible in MoI - or any other CAD come to that?

All I want to do is extrude some text and apply a 45 deg bevel/chamfer to the upper edges, so that they all converge, to achieve an apex along the centre of each letter. Pretty much like number/letter stamps, or the roof of a house.
I've tried all the ways I can think of, but can't seem to crack this one. Does anyone have a quick and reliable way of doing this?
Thanks in advance, for any replies.

Martin.
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Michael - this is an example of what I was talking about a few days ago - specifically the ability to have a chamfer or fillet join in the middle (without overlapping - kind of like a 100% fillet/chamfer)

http://moi3d.com/forum/messages.php?webtag=MOI&msg=3713.1

Hi Martin,

As linked to by NightCabbage, Michael explains the problem and a workaround.

It can be quite quick to construct a center line on the text, then from that, construct the lines needed for a sweep/loft.


A quick example:-

"It can be quite quick to construct a center line on the text ..."

What's the easiest way to get a center line?

Ed

Hi ED,


You would need to build construction lines.

On the text, pick midpoints where possible, then draw to perp on opposite edge (or in the case where you have the angled parts of the letter "M", then any point to perp) you can then get the midpoints/intersections of those construction lines.

This took about 2 mins.

Oh, perhaps I should have said that I want to do this on the Times New Roman font, which is quite a bit more complicated than some of the others. Thanks for the replies though.

Martin

>>I want to do this on the Times New Roman font, which is quite a bit more complicated than some of the others.<<


So you cannot create center lines on that text?

I suppose the hardest part would be deciding what is the correct output, in that where the chamfer intersects on the apex.
Sound like a bit of a challenge to me. I will have a play a little later to see what I can come up with.


- Steve

There is a great thread in cnc zone with some programmers discussing this...

http://www.cnczone.com/forums/showthread.php?t=99356

On block text, it is very easy... With something like "Times New Roman", it can becaome a very complicated issue to work out..In this thread he has created a custom program to do the times new roman cut..."Manual labor"..

Your best bet is to get out your drawing tool and draw it using the supplied tnr font as a guide.

Here's a quote from his tip on drawing the times New roman font centerline...

""""""""An analysis of the outline of the Times Roman upper case I, chosen for simplicity, leads rapidly to a general method of finding the centre line tool path.
This was done by placing a series of circles inside the outline, each with its own centre marked, so that the circles just kissed two sides.
See fig 1.
A line was drawn to join up all the centre spots, and inspection of this path suggested that two arcs would make a close approximation, with a short straight line at the end.
""""""""""""""""

Hi Martin,

> Oh, perhaps I should have said that I want to do this
> on the Times New Roman font, which is quite a bit more
> complicated than some of the others. Thanks for the
> replies though.

Also, what is the particular text string that you want to do this to?

But yeah Times New Roman has all kinds of varying widths and little serif parts in each letter so it's going to be more difficult to try and get a center line curve on something with those kinds of varying shapes in it.

Also your original post you wrote:

> All I want to do is extrude some text and apply a 45 deg
> bevel/chamfer to the upper edges, so that they all converge,
> to achieve an apex along the centre of each letter.

Like Steve mentioned above, you may need to decide a bit more specifically about what the correct output is supposed to be.

These may be kind of mutually exclusive things you are trying to do here - if you have something of variable width, then putting a 45 degree angle bevel on it will not result in the bevels colliding together at an actual single z level center line.

So the overall goal would need to be specified a bit more clearly I think - would you want to emphasize 45 degree sides and have a colliding centerline of varying height? Or would you want to have a single height centerline with something other than 45 degree angle sides?

One thing you could do would be to draw a 45 degree line and sweep it along the outer path of the letter, that may give you some pieces to work with, like this:



That will generate some overlapping pieces in the compressed areas:



But you can then trim those surfaces to cut them back to where they intersect with one another:




There you can see the kind of "varying height" result where various 45-degree angled results from variable thickness areas are colliding. If the intersection was done from the holes outward as well even the main center line would have that kind of varying height which I suspect you would not want. So you may be looking for some kind of hybrid result, with "45-degree"-ness emphasized in some areas (possibly on the outermost contour?) and "even z level" emphasized in others... Or maybe a totally even z level is more important to you? In that case you won't be able to get 45 degree angles on things then...

At any rate, you can see that it's not a very simple problem, and there seems to be some mutually conflicting constraints in the original problem statement.

- Michael

Hi Burrman,

I have had a quick look at the thread you linked to. I am seeing that as a possible solution to using a single cutter giving a result of a variable depth cut. I will look more at the thread later, but I did not see a way to catch the problem from the need of a circle from 4 points at the corner intersection of various letters.



- Steve

Well in all honesty, I don't really want beveled text at all. What I'm trying to do is actually linked to Greybeard's thread on the CNC Zone and that is to find an easy way to create and then extract the centre line from the 45 deg surface of the text characters, along with the Z depth information. If I can do this easily, it will allow me to do VCarve lettering on my CNC miller. So far, I've come up with a couple of ways to do it, but there always seems to be something that makes the process long winded, although not impossible. I find the tangent circles method is a very time consuming way of doing it manually.
Here's a pic of 1 letter that I've run through the process and simulated in CutViewer.
Martin.

Hi Martin,

> to find an easy way to create and then extract the centre
> line from the 45 deg surface of the text characters, along
> with the Z depth information.

The line where the 45 degree angle surfaces intersects will be of varying height though.

If that's what you want though, you can use a similar technique that I posted earlier - draw a 45 degree angle line and sweep it around the curves. This will produce all kinds of crazy surfaces but then you can run the Construct > Curve > Isect command to generate the intersection curve between those surfaces.

You may want to do something like use Edit > Separate on the text path first so that you have all separate curve pieces for the path, that will prevent MoI from doing its own intersections to produce mitered corners. You may instead need to do some extensions yourself in that case though.

Here's an example - here I drew a 45 degree angle line in the Front view and moved it off to the side (this will active "auto place" mode for sweeping), and used Edit>Separate on the text to break it into individual segments:



Select the angled line, then run Construct > Sweep, and pick all the path segments as the sweep rails. That will generate a result like this:



Now select all those surfaces (easy way to do that is to use the Scene browser Types section, click on the text for "surfaces" in that section to select all surfaces), and run Construct > Curve > Isect to generate intersection curves. That will produce this:



Delete all those surfaces now (again use the Types section of the scene browser to select them more easily), and you are left with this:



Now you can go to each of those corner areas and clean them up using Edit > Trim, select 3 pieces like this:



Then run Edit > Trim, and right-click to indicate you are doing a "mutual trim" where all the objects are cutting each other, and pick these fragments to discard:



That will leave you with a corner like this:




If you repeat that on the other corners, you will get a result like this:



Or as seen from the top:




- Michael

Hi Steve...

""""""""""I am seeing that as a possible solution to using a single cutter giving a result of a variable depth cut.""""""""

Well yes that is Greybeards ultimate goal. I posted the link for 2 reasons. In the very begining, he gives his method to prgamatically determine centerline for the times new roman charater.. He just iterates through tangent circles then draws a curve through points with the circles center points to create centerline.... The rest of the very arduous thread, gets into some other discussion like you mention, but also touches on the various complexities of "What is really the centerline anyway???"

Here' s the file I was going to present with the initial greybeard iteration:



But that was just blown out of the water with Michaels isec example with some quick trims... Way more work to create each letter with my method...Less than a minute to create the curves with MG's, then some setup for sweeping surfaces....

Found one cool thing in Michaels method... When you run isec...Just click the right mouse button "twice", which will run the isec on the curves a second time and create "points" at their intersections, which helped me visualize the areas I needed to focus on....Bonus!!!

Anyway...

Hi Burrman,


Michaels methods is quick, although I would avoid using the actual letters for the surface creation.
The letters are OK for printing etc, but for smooth curves they can be quite bad, and would rebuild them before using them for building the surfaces.


- Steve

""""""""""although I would avoid using the actual letters for the surface creation. """"""""""""""

Hi Steve,
Could you explain what you mean here? Here is the Times New Roman "I" from Michaels example, and i dont really see anything wrong with the surfaces created. This one was done with sweep. I also did one with loft that produced a surface with less control points in it... But it appears they both make a smooth usable solid.... ?????

Are you refering to just "fonts" in general as being poor geometry to start with?

Yeah often times fonts can have pretty messy curve structures, things like many small segment fragments, slight kinks in between pieces instead of being tangent, stuff like that.

Those kinds of things don't particularly have an effect on making a 2D filled outline (which is what they are originally created for) but can be not so good for treating them as 3D geometry. So a rebuild step could be a good idea.

But Times New Roman itself seems to be pretty cleanly constructed though, so it's possibly one case where it may not be necessary.

- Michael

Hi Burrman,

>>Are you refering to just "fonts" in general as being poor geometry to start with?<<

Yes.

A simple example would be the capital A in that font, if you explode/separate the curves you will find where the curves split due to bad curvature. .



That causes the sweep to create joined surfaces around that section

In may not matter, its probably just me liking continuous surfaces where possible.



edit. It took me that long to write this, that Michael got a post in first. I am slowing too much these days LOL.

That's not particularly bad though, when fonts get messy they can get a whole lot messier than that, like 10 times as much segmentation...

Hi Michael,

Yes,
I have seen numerous times where users of nurbs applications have been trying to put rads around solid text edges then they wonder why it can fail.


- Steve

Generally fonts are created for a 2D use :)
It's an artificial mode to have them in 3D
It's an another work to make an alphabet in 3D :)
The famous Dürer one ;)