Getting fillets to work on 3D solids

I am dabbling with a small machine part. I've done a lot of architectural
modeling but little mechanical, thus filleting has not been needed in this
regard.

Anyway, I have several parts which are rounded pieces. Specifically, closed
polylines made up of a few arcs, then extruded. A simple geometry,
actually. When I try to apply a fillet to the 3D solid, I can do so just
fine on SOME of the arc edges, but others result in an error similar to the
following:

"Could not find acceptable sequence of capping faces to trim blend face.
Failed to perform blend
Failure while filleting"

Why would this be? The radius is certainly small enough to be possible.
The arcs meet almost tangental to each other (no sharp angles). I have
tried various radius settings and other settings I can think of. No luck.

Has anyone had a problem like this? More importantly, has anyone SOLVED it?

Any ideas how to work around? For instance, different ways to draw? Some
unknown variables? Any code fixes?

I need to make this work, somehow, and modeling this shape with a fillet
would be exceedinly difficult.

 

Post the geometry.

 

Try redrawing the profile using a NORMAL line then extrude and fillet or a poly line with zero width making sure you used the close option to finish the profile.
I am dabbling with a small machine part. I've done a lot of architectural
modeling but little mechanical, thus filleting has not been needed in this
regard.

Anyway, I have several parts which are rounded pieces. Specifically, closed
polylines made up of a few arcs, then extruded. A simple geometry,
actually. When I try to apply a fillet to the 3D solid, I can do so just
fine on SOME of the arc edges, but others result in an error similar to the
following:

"Could not find acceptable sequence of capping faces to trim blend face.
Failed to perform blend
Failure while filleting"

Why would this be? The radius is certainly small enough to be possible.
The arcs meet almost tangental to each other (no sharp angles). I have
tried various radius settings and other settings I can think of. No luck.

Has anyone had a problem like this? More importantly, has anyone SOLVED it?

Any ideas how to work around? For instance, different ways to draw? Some
unknown variables? Any code fixes?

I need to make this work, somehow, and modeling this shape with a fillet
would be exceedinly difficult.

 

I've been in the same boat - a pain indeed.

Often, I find I can slice the part in halves or quarters, fillet the
pieces separately, then union them back together. At least this can
isolate where the problem is occurring and maybe a clue about how to
model things differently so you don't get stuck. Maybe slice at the
transition points where curved edges meet straight edges.

I've sometimes scaled a part up by 10, fillet with a 10x radius, then
scaled it back down again. Whatever it takes...

Good luck.

-Bill

============

 

Hate to sound ignorant but how would I post it here? Should I use uuencode
or something? (I haven't had to post on a newsgroup in the past, usually
just web-based blogs)

I can post a very simple example of the geometry and a minor modification
which made it almost work.

 

Hmm. I should have thought about slicing the part. Good idea. I will try.
Scaling, eh? That actually works? Any more than just changing the units?
You'd think the code would be smart enough to avoid problems like that.
Which is why I wonder why there's no "fix" available, or that an updated
version of ACAD wouldn't work better (I'm using ACAD 2000).

 

Not sure what you mean by "normal" line, unless you mean drawing the
segments first then converting to a close polyline? That's what I did,
actually. I made 4 arcs, 2 to generate the long curve, 2 for each "end",
then converted to a polyline, then extruded.



Try redrawing the profile using a NORMAL line then extrude and fillet or a
poly line with zero width making sure you used the close option to finish
the profile.
I am dabbling with a small machine part. I've done a lot of architectural
modeling but little mechanical, thus filleting has not been needed in this
regard.

Anyway, I have several parts which are rounded pieces. Specifically, closed
polylines made up of a few arcs, then extruded. A simple geometry,
actually. When I try to apply a fillet to the 3D solid, I can do so just
fine on SOME of the arc edges, but others result in an error similar to the
following:

"Could not find acceptable sequence of capping faces to trim blend face.
Failed to perform blend
Failure while filleting"

Why would this be? The radius is certainly small enough to be possible.
The arcs meet almost tangental to each other (no sharp angles). I have
tried various radius settings and other settings I can think of. No luck.

Has anyone had a problem like this? More importantly, has anyone SOLVED it?

Any ideas how to work around? For instance, different ways to draw? Some
unknown variables? Any code fixes?

I need to make this work, somehow, and modeling this shape with a fillet
would be exceedinly difficult.

 

Or you can download the trial version of Rhino, which is very robust.

 

Ah I see now. Unfortunately this is one of the limitations with AutoCAD. If you can get access to MDT then it should be able to handle this with out any problems.
Not sure what you mean by "normal" line, unless you mean drawing the
segments first then converting to a close polyline? That's what I did,
actually. I made 4 arcs, 2 to generate the long curve, 2 for each "end",
then converted to a polyline, then extruded.



Try redrawing the profile using a NORMAL line then extrude and fillet or a
poly line with zero width making sure you used the close option to finish
the profile.
I am dabbling with a small machine part. I've done a lot of architectural
modeling but little mechanical, thus filleting has not been needed in this
regard.

Anyway, I have several parts which are rounded pieces. Specifically, closed
polylines made up of a few arcs, then extruded. A simple geometry,
actually. When I try to apply a fillet to the 3D solid, I can do so just
fine on SOME of the arc edges, but others result in an error similar to the
following:

"Could not find acceptable sequence of capping faces to trim blend face.
Failed to perform blend
Failure while filleting"

Why would this be? The radius is certainly small enough to be possible.
The arcs meet almost tangental to each other (no sharp angles). I have
tried various radius settings and other settings I can think of. No luck.

Has anyone had a problem like this? More importantly, has anyone SOLVED it?

Any ideas how to work around? For instance, different ways to draw? Some
unknown variables? Any code fixes?

I need to make this work, somehow, and modeling this shape with a fillet
would be exceedinly difficult.

 

MDT?

It's too bad ACAD can't handle this, since it seems pretty straightforward
if the programmers would bother to fix it...


Ah I see now. Unfortunately this is one of the limitations with AutoCAD. If
you can get access to MDT then it should be able to handle this with out any
problems.
Not sure what you mean by "normal" line, unless you mean drawing the
segments first then converting to a close polyline? That's what I did,
actually. I made 4 arcs, 2 to generate the long curve, 2 for each "end",
then converted to a polyline, then extruded.



Try redrawing the profile using a NORMAL line then extrude and fillet or a
poly line with zero width making sure you used the close option to finish
the profile.
I am dabbling with a small machine part. I've done a lot of architectural
modeling but little mechanical, thus filleting has not been needed in this
regard.

Anyway, I have several parts which are rounded pieces. Specifically, closed
polylines made up of a few arcs, then extruded. A simple geometry,
actually. When I try to apply a fillet to the 3D solid, I can do so just
fine on SOME of the arc edges, but others result in an error similar to the
following:

"Could not find acceptable sequence of capping faces to trim blend face.
Failed to perform blend
Failure while filleting"

Why would this be? The radius is certainly small enough to be possible.
The arcs meet almost tangental to each other (no sharp angles). I have
tried various radius settings and other settings I can think of. No luck.

Has anyone had a problem like this? More importantly, has anyone SOLVED it?

Any ideas how to work around? For instance, different ways to draw? Some
unknown variables? Any code fixes?

I need to make this work, somehow, and modeling this shape with a fillet
would be exceedinly difficult.