Good Morning, all...

I thought I'd pass on a lesson learned from my first prototype in MOI.

I needed to engrave text into the surface. I discovered two things.
1. Not all fonts are good candidates for engraving when the cavity created needs to be chamfered or filleted.
2. It is better to chamfer or fillet the bottom of the fonts before pushing them into the surface.

I made the mistake of selecting a font, creating the text and pushing the font into the surface and then trying to chamfer the edges of the engraved text. First, it is difficult to find the edges of a character engraved at 1/128" below the surface. Secondly, it is difficult to know how deep the text has been pushed into the surface. Finally, not all characters worked.

I found that if I created the font twice as high as I needed, chamfering the bottom slightly higher than the depth needed, a chamfer line was created to be used to help define the depth of your push into the surface and when the text was differenced it left behind a perfectly chamfered cavity. A lesson learned.

Regards

One important tip for working with small or tiny dimensions, based on Michael's recommended practice, scale up your model say, 10X (or more). When your finished, reduce it back to its actual or original size. See post 4 of this thread for an example: http://moi3d.com/forum/index.php?webtag=MOI&final_uri=&continue=Continue

Leonard

Hi Bob, yeah fonts can be pretty challenging to fillet or chamfer because they often have a lot of sharp angles in them, and sometimes they can have kind of messy curve structures since they were originally designed for just making 2D text which is much much less finicky about stuff than things like a fillet calculation.

One thing you might try when you want to use a particular font is to create it as curves only initially, and then select those curves and turn on the control points with the Edit > Show pts command.

If the control points look pretty chaotic like with a zillion more points than you thought would really be needed, then that might be a fairly messy font. One thing that can help to clean up some things like that is the Rebuild command:
http://moi3d.com/2.0/docs/moi_command_reference10.htm#rebuild

Also if you make a solid version of a font and its sides seem to be broken up into a lot more fragments than what would really be wanted, that may mean the font has little segments in it that are not quite smooth to one another, causing a lot of little faces to be created for the side walls part when it gets extruded. That's also not great for filleting as well. Running the Rebuild command on the curves before extruding them can also help to glue together curves that are fragmented into some smaller segments like that into longer segments which can then avoid making so many little faces on the side walls.

- Michael

Thanks, Michael....I'll certainly try your suggestions. When I could not chamfer or fillet a character a closer inspection showed small breaks in the outline of the character. I've found a font and tested every character in the alphabet as I've mentioned on my other post. Regards

Hi Bob,

Most of my work in MoI is used for making jewellery Masters which have text within them & that are milled in wax for casting.
So thought I'd offer up some Tips via an Example file that seem to work for me (or at least for my workflow/style).




With regards to Fonts, I went through them & noted which ones that will work for me without too many headaches.
With that list I then setup 3DM files for each Font & saved them as Templates with each letter as a curve & edited each using "Points".
This way I'm able to open whichever Font Template I need & just Copy & Paste into the job I'm working on.
In your case if you intend using only one style of Font, then this shouldn't be too hard or time consuming to do.

Because of the scale that I work at & the Conical Cutters used to mill with, I tend not to worry too much about fillets or draft angles.
It's mostly too much depth on small text that'll cause me dramas in the Rubber Moulds, so I typically stay at about 0.35mm to 0.4mm depth.
Obviously this wouldn't apply in your particular case.

I typically position my Text over the top of the surface & just use "Trim" to cut the surface with instead of the "Project".
With the surface now cut, I just select those "Surface Text" items & use "Shell" to accurately get the required depth I'm wanting.
The "Shell Text" gives you a Solid, so you'll need to remove the very top surface of the text by clicking on it twice aka "drilling down".
Then all you need do is "Delete" that top surface & you'll have a recessed piece of text.
With letters like "A,a,B,b,D,d,e" etc, you'll need to "Join" their centre surfaces as required onto their newly opened "Shell Text".
To finish, select all the "Shell Text" & the surface or items they're to be part of & use "Join".
So assuming your original starting surface came from a Solid & that you've done everything correct, rejoining it should produce a watertight Solid again.

HTH, Colin

Thank You, Colin...sorry I was so long in responding. I wasn't expecting any further
comments. I will experiment with your suggestions. I'll have to brush up on "Shell".
One question -- it looks like you're able to follow the contour of the surface. Is
that possible with your technique? I'm attaching an example of both an engraving
and embossing on one of my designs. I do, periodically need to engrave text into
a rounded surface. Thnak you for the tip...Regards...Bob

Hi Bob,

"One question -- it looks like you're able to follow the contour of the surface. Is
that possible with your technique?"

You're able to get reasonably good results on most contours, but it'll all depend on what you're aiming for.
Looking at your example, I can't see anything that immediately screams problems.

Where things tend to go astray is when you're wanting to run a length of text around a complete circle.
What you can't do is a "Flow" or a "Flow Along Surface" type of command, so which is why I have Rhino. (plus I use it to render with VRay)
I first work all of my setups within MoI & then Copy the items needed into Rhino to used with it's Flow or FlowAlongSurface.
That way I can be sure that any text spacing, alignments, etc; remaining correct.
I then use those curves to Trim the surface of the ring & Shell those sections, in much the same way as I've described previously.

I'm hopeful that by the end of MoI V3, we may possibly get something like these "Flow" commands, but that's purely up to Michael.

Here's a couple of renders for models that required "Flow" to get the text all laid out correctly & to suit their particular ring shapes.

HTH, Colin

Good Morning, Colin...

Thanks for the feedback. I encountered three issues when trying to add text to
a curved surface. The depth into the surface; the percentage of chamfer or fillet;
and, following the curve. In green sand casting, all vertical surfaces (z axis) must be
angled (draft) at least 3 degrees from vertical (z). If you try to follow a curve that
has chamfered text, the chamfer degrees will be less than 3 degrees on one side
of the character and more than 3 degrees on the other, relative to vertical (z axis).
I can see this would introduce a huge programming problem, I've not seen solved
in any of the 3D packages I'm familiar with.

Other casting techniques such as lost wax, etc., can accommodate the problem,
but, for green sand casting you almost have to increase your angle of draft and
add the text as the final step in the process.

Regards...Bob

Beautiful renderings Colin!

Michael T.