Convex Lettering

[joewino]

I am trying to cut some convex letters out of HDU. Using ArtCam Pro and a 120 degree bit I can make the top of the letters covex, but the thinner strokes of the Americana font are lower than the thicker strokes. I would like for all the strokes to join at the same height.

Is this possible, and if so, how do I do it?

[bleeth]

Raymond: You have asked Pro to do something that there was much discussion on a while ago. The bottom line answer is no. That requires a change in pitch (incline) in the various line weights and Artcam just can't do it unless you turn your letter carving into full relief carving rather than v-carving and spend a whole lot of time cutting with a small bit and small stepover.

Dave

(Note to Joe: Didn't you solve this with some other software)

[Brady Watson]

You will need to do a 3D toolpath using the 2D vectors (or other vector) as a boundary to get your curved tops all the same height. ArtCAM makes it easy to create these types of letters. I don't have that font in my system, so I picked one with small serifs that would be tricky to do the way you describe:


6333

The ISO-Form letters tool asks you to define the top dome height and wall height. From there, use the same vectors to toolpath and you are ready to go. You do not want to cut these with a 120° to get the look you want. Use that 120° Vee on prismatic letters.

Does that answer your question?

-B

[joewino]

Brady...well, kind of...but I want a convex letter, not a rounded over letter. I guess the term convex is not as accurate as I need...prismatic is probably a better term.

Can I use the 120 degree V with that and still get all the strokes the same height? I tried the ISO-Form (using the V tool) but still got the same results.

If the V tool isn't used, what is the procedure otherwise?

Thanks for all the quick responses.

[Brady Watson]

Ray,
Wide to narrow strokes of the letter are going to vary in height, no matter what method you use. I don't think that it is possible to do what you are asking, but I could be mistaken (I think that somewhere it violates basic rules of geometry...there are only so many possibilites when the angle must remain constant) Imagine the apex of larger letter portions and where it would be in 3D space/z-height...now imagine the smaller portion if it had to be at the same height in Z...the angle would surely not be the same and the letter would look downright goofy...for lack of better term.

If you used a different font, like Arial Black, then yes, I believe that it is possible because the letters are square. Once you start trying to add an angle to a letter, regardless of method (IE Prismatic letter TP, Shape editor, Iso forming) the program takes into consideration the shape of the letter and applies the 3D portion.

In terms of prismatic letters, which I think is the term that you are looking for, they vary in height, just as v-carving varies in depth. All of the prismatic letters that I have cut all vary in height.

Can I ask why you are stuck on maintaining constant heights? The idea behind prismatic letters is that they pop out at you, just like v-carving when it is cut with the proper bit, jumps out at you...the eye is unsure whether it is positive or negative relief.

-B

[joewino]

Brady - thanks for the information.

The reason that I wanted all the strokes at the same height is that when I hand carved these letters I would make all the strokes have a uniform height. Just wanted to achieve that same look.

I have done some samples on my ShopBot and they came out very nice...so I'll just go with that. Probably no one will ever know the difference.

Thanks all for all the assistance you willingly give.

[joe]

Howdy Folks,

Way back when I started with my router, I had the same desire as Raymond on the subject of prism letters. I posted to adnosium on the subject.

As Brady and Dave had stated, one way to get what Raymond and I want is with 3D. Then it's necessary to finish up with a chisel. I haven't found a 3D routed model, to date, which couldn't be improved with the aid of a razor sharp blade. There's also the technique of doing a profile cut, then finishing up with carving tools. This may be the best way to control bevel depth while maintaining the creative look. This method has one major drawback however, there's a carving skill requirement.

Brady's question as why it's sometimes desireable to control the height of thin architectural letter parts, and there sharp intersections is to the heart of the subject. The visual impact almost defies a verbal description.

Perhaps this link to one of our Letterhead friends will help. Try the slide show!

www.bernhardtsigns.ca (http://www.bernhardtsigns.ca)

Happy carving

J.

[Brady Watson]

Joe,
Thanks for the clarity. I'm not a signmaker and was curious as to why one would want consitent height. Thanks for the link to the slideshow! Gorgeous stuff on there!

-B

[normand]

Can you 3d raster only the letters on your hdu. Not the whole project? That would be faster sometime there is no need to raster everything with a small ballmill,especialy all the flat background if the back is flat of course.