Hi,
I have about 10 days going work with the MoI trivial-version and nothing going good. All Videos have seen...
Here my description, to doing:

First time designed a seal for cnc (attachment as a Adobe.ai File).
I load the file to MoI and my wish: the Letters going 3 mm deep in the round plate. Inside the letters are speces the going 3 mm high. The circel def. the plate and it ist 5 mm high.

Please let me now, what is the normal way?

Thanks all for helping.

Dieter

Hi Dieter

Open Moi and at the bottom right, select Options then General and set units to mm.

Select circle and Construct Extrude it -5.0 mm.

So do you mean to indent the letters by 3 mm? If so, the letters need to be removed from the round disk (somehow).

- Brian

Hi Dieter - the basic process that you'd use would be to extrude the circle downwards 5mm, then extrude the letters downwards 3mm and then select the circular solid, run Construct > Boolean > Difference and then select all the letter pieces as the cutting objects to cut them into the larger circular piece.

However, before you can do any of that you're going to need to clean up the curves because there are numerous places where your curves are "self intersecting" - where the curve has a sort of little loop in it where it crosses back over itself. This is what is likely causing you the most problems - when a curve crosses back over itself it no longer defines a proper inside and outside region and so it won't be possible to get a proper solid extrusion from it you'll get something that's weird and messed up in some way maybe without a top and bottom end caps or something like that.

Here's an example of one area of "self intersection":






Notice the little loop back over itself in the second curve in that corner area. To get a proper result you can't have any of these at all and you currently have one at every single sharp corner it looks like.


Another thing that could be problematic is the very short distance between the 2 outline curves, meaning this distance here:



Those curves are only about 0.08 units apart from one another, it can be difficult for the system to handle pieces that come so close to one another because at a certain point it decides they are close enough to need to be merged with each other. It's possible that they may be just far enough apart that it could maybe be ok but that's another possible problem area with your current curve layout, it tends to be better if surfaces and solids that you create don't have such a super thin areas in them like that.

If you try to extrude both an inner and outer outline like that at the same time, (if there were no self intersections), the extrusion would try to make only a super thin solid out of it, it would interpret the inside outline as supposed to be a hole.

- Michael

I selected all the edges and extruded -3.0 mm.
The result is joined srf, not solid. (Due to problems per Michael)
Managed to do a Boolean Difference, but had to play around a bit...Not sure of exactly what I did...

- Brian

Edit, deleted attachment, as it must be a little flawed...

Hi Brian, re: Joined srf instead of solid, that's going to be because of the self intersections, see my above post I think we were replying at the same time there.

- Michael

Hi Dieter, so probably the easiest way to clean it up is to delete all the inner outlines and then rebuild them in MoI using MoI's own Construct > Offset command. MoI's curve offsetter will likely do a better job on those corner areas, it should probably get them all to be proper sharp corners rather than having little loops.

There are a few self intersections in the outer contour too though which will need to be cleaned up first, but there are fewer of these so it's probably an easier route, clean these up and then use Construct > Offset in MoI to build the other contour maybe at a slightly larger thickness though.

Here are the 3 areas that I found so far with self intersections in the outer contour, it's possible there may be more you need to zoom in a ways and move around and inspect it to make sure it's well formed:


- Michael

My version, to be deleted in a few days :-)

What CNC program are you using?
I think Aspire would just need a png of the letter curves...

- Brian

Thank you Michael.

Is there a tool or script to discover self intersections?

- Brian

Hi Brian,

> Is there a tool or script to discover self intersections?

No, not that I am aware of. There can be a slight visual cue that the curve can tend to look a bit darker in self intersection areas because places where curves are drawn more than one time will be slightly darker, it's subtle but that sometimes gives me a bit of a clue where to zoom in and examine more closely.

- Michael

Hi Dieter

Just thought that for a "Stamp," the mirror image may be appropriate.
If to, do positive 5mm and 3mm extrudes.
The client might not want to look in a mirror to read the letters... :-)

- Brian