As usual, I've been done in by the fillet engine. But at least this time, I know why. As can be seen in the tight bend of the "9", the fillet engine cannot make sense of the space than is smaller than the radius of the requested fillet (.008). Knowing is half the battle, but I am still not at the point where I can get myself out of trouble.

Suggestions please on how to open up or rebuild the problem section of the number so it will fillet properly.

File lives here for anyone that is interested:
http://www.mediafire.com/?2adbwx1a8lp2jea

Thanks!

Chris

seems you have upload the STL file!
Moi can't reload this format!
You must upload the 3DM format ;)

Doh!

Correct Moi file now lives here:
http://www.mediafire.com/?2adbwx1a8lp2jea

Sorry for the mixup, but thanks to those who bothered to look. =)

Chris

Hi Chris,

I am showing the highlighted suspect surface:




I deleted it, and a "floating" edge was revealed.




I hope this info helps.

Michael T.

Hi Chris, yup Michael T is correct there is a kind of mangled surface in that area.

It looks like there was at some point a little surface piece here:



But the edges of that little piece have gotten kind of manged somehow, a couple of those surfaces are probably going to need to be removed, I'll see if I can tune it up for you.

- Michael

Hi Chris, so the tricky part is that little surface that I shaded in red above has its edges manged enough that it is not able to be drawn in the shaded display which makes it hard to pick to get rid of it.

In order to get it you have to do a window select around it, a click won't actually be able to grab it since there is no shaded spot to click on.

Normally to do a window select you start in some empty area and drag the mouse, but when you are zoomed in close to a small area like this there is no convenient empty area to click on. There is a trick for such circumstances which is to hold down Shift+Control when dragging your window, that will avoid doing any regular selection on the initial click and instead go directly to window selection. Then you want to do a window selection starting from the left and going towards the right to do the kind of window that only grabs things entirely inside the window (starting on the right and going towards the left does a "crossing window" that grabs anything that intersects the window even partially).

- Michael

Hi Chris, so once that little mangled ghost surface is removed, there is still a problem in the trimming boundary for the adjacent pieces, you can see there is an unusually large gap between the edges in the outer surface's trimming boundary here:



Those surfaces may need to be untrimmed and retrimmed to repair that, I'll take a look.

- Michael

Hi Chris, I've attached a fixed up and filleted version.

So the actual bug was in some previous step that kind of collapsed that small surface fragment's edges down into nothing.

I'll see if I can track down where that was happening, it can sometimes be difficult to find exactly what caused something like that looking at just the final result though.

You may want to run the Rebuild command on curves before constructing a bunch of stuff out of them, especially if they're going to be filleted - the Rebuild command can simplify the curve structure and combine pieces together so there aren't so many little separate segments. When you have little surfaces that are small enough to where they are approaching the fitting tolerance it can cause some difficulties in handling them, it can cause some kinds of algorithms to think that opposite sides of the surface are close enough to get fused together and stuff like that.

- Michael

Michael (and all) thank you for your help. As usual, this is the greatest user forum on the net.

I made the circular text in Illustrator and then "created outlines" and the brought it into Moi. This was then extruded and scaled and positioned over the dome of the wheel. The dome was then duplicated and moved above itself .xx units (I forget LOL) This piece was then used for a boolean difference to give the letters a curve that matches the domed face of the wheel.

Does that makes sense?

I'm wondering if the little problem piece started with Illustrator, or when it was extruded.

Thanks again!

Cheers,

Chris =)

If you don't mind me jumping into this thread: I guess It started in Illustrator. The "9" looks particularly messy (point-wise) compared to the "8" and the other letters. Sometimes the paths in (especially free–) fonts aren't closed, or have point angles that cause the paths to overlap in tiny areas, which leads to little surface pieces being generated.

Greetings,
Sebastian

Hi Sebastian, yeah the 9 from Illustrator is definitely not as clean as the other characters. But it doesn't seem to have any self-overlapping in it which I thought could have been the problem.

I think that the model getting messed up was probably a bug in some calculation in the geometry library that did not deal very well with having a small slivery surface fragment to deal with, I'll do some investigation to see if I can pinpoint the area. I have fixed up some problems with small fragments in the past in some various areas.

In the meantime though the Rebuild command can be used to help simplify curves like this (Rebuild command description here: http://moi3d.com/2.0/docs/moi_command_reference10.htm#rebuild )

The initial curve point structure looks like this (as you showed above):



If you select it and run the Rebuild command on it with a tolerance of 0.001 units, it will reconstruct them to get this result instead:



That's a much cleaner result - one of the things that's particularly better is that there are not so many internal corner points in it, so it can be edited better.

One of the problems with AI curves imported into MoI is that they're basically made up of little bitty bezier pieces stuck together, and if you edit the curve in MoI it can fragment into one segment for each piece, since those pieces have a kind of limited smoothness to one another (they're tangent where they meet but not curvature continuous).

There are a few different things I can do in MoI improve this - if I can find the bug that mangled things when processing that slivery piece that would be one thing, but I may also try to do some kind of automatic curve rebuild process when bringing stuff in from AI format or from font data. It would also probably help if I turned down the thing that dices up edited curves at curvature discontinuities and only diced things automatically at tangent discontinuities instead.

But before any of that is in place, it can be a good idea to do a manual Rebuild on stuff coming in from AI or from fonts.

- Michael

Well it looks like "rebuild" will now become an essential part of my work flow. I don't mind making the change, as it will have an obvious positive effect on my work.

Thanks!

Chris