Path rule bug (on inside corners) ???

Having problems with or questions about SheetCam? Post them here.
Post Reply
mancavedweller
Posts: 100
Joined: Tue Feb 25, 2014 6:53 am

Path rule bug (on inside corners) ???

Post by mancavedweller » Sat May 18, 2019 6:34 pm

Hi Les,

having a problem with one of the path rules (on inside corners).

I drew a shape in cad to have two 45 degree angles, a 90 degree angle, an angle less than 45 degrees, and an angle greater than 90 degrees.
I also gave the shape perpendicular/90 degree leadin/leadout.

I created a rule On Inside Corners tighter than 50 degrees, expecting the rule to be applied to the two 45 degree inside corners and the tightest inside corner.

However, the rule is being applied to ALL inside corners plus the perpendicular leadin and leadout.

Is this a bug or something I'm missing. Job file attached.

Keith.
PATH RULE BUG (INSIDE CORNERS LESS THAN 50).jpg
PATH RULE BUG (INSIDE CORNERS LESS THAN 50).jpg (46.66 KiB) Viewed 664 times
PATH RULES TESTING (inside corners).job
(5.61 KiB) Downloaded 6 times

User avatar
Les Newell
Site Admin
Posts: 2289
Joined: Thu May 11, 2006 8:12 pm

Re: Path rule bug (on inside corners) ???

Post by Les Newell » Sun May 19, 2019 12:05 pm

In this case 'inside' and 'outside' are probably a little confusing. An outside corner is any corner where the cutter has to roll around the outside of a corner. An inside corner is where the cutter is going into a corner and has to make a sudden change of direction. In your example all of the inside corners are triggering a rule.

If you are cutting outside a shape the names make a bit more sense.

mancavedweller
Posts: 100
Joined: Tue Feb 25, 2014 6:53 am

Re: Path rule bug (on inside corners) ???

Post by mancavedweller » Sun May 19, 2019 12:23 pm

OK, I >>THINK<< I understand that.

So an inside corner is any corner less than 180 degrees. This causes a sharp change in direction of the tool.

On the contrary an outside corner is any angle greater than 180 degrees and therefore the tool rolls around the corner. And therefore on an "inside offset" cut (as my drawing is), we can have both inside and outside corners.

I seen the "roll around the corner" thing yesterday when playing with the "On Arcs" rule and the rule was also applied to outside corners because the actual tool path was an arc going around the outside corners. On a side note regarding that, would it not be a good idea to disable the "On Arcs" rule being applied to outside corners, or at least have a tickbox option to enable/disable it ? I initially thought it was a bug when corners had the rule applied too.

Getting back to my "On Inside Corners" issue, all of the corners in my drawing are less than 180 degrees and therefore inside corners. So with a "Less than" setting of 50 degrees, shouldn't the rule still only be applied to inside corners less than that angle. I mean is the overall meaning of the rule:
"On inside corners that have an angle less than 50 degrees" ??

Or am I still not understanding something.

Keith

User avatar
Les Newell
Site Admin
Posts: 2289
Joined: Thu May 11, 2006 8:12 pm

Re: Path rule bug (on inside corners) ???

Post by Les Newell » Sun May 19, 2019 2:09 pm

mancavedweller wrote:
Sun May 19, 2019 12:23 pm
So an inside corner is any corner less than 180 degrees. This causes a sharp change in direction of the tool.

On the contrary an outside corner is any angle greater than 180 degrees and therefore the tool rolls around the corner. And therefore on an "inside offset" cut (as my drawing is), we can have both inside and outside corners.
Yes, that's correct. However it is better to think of a straight line as 0 degrees, an outside corner is a positive angle and an inside corner is a negative angle. We are after all interested by how sharply the cutter has to deviate from a straight line.
On a side note regarding that, would it not be a good idea to disable the "On Arcs" rule being applied to outside corners, or at least have a tickbox option to enable/disable it ? I initially thought it was a bug when corners had the rule applied too.
I'm not sure. The corners in that case are arcs. Is there a situation where this would be a problem?
Getting back to my "On Inside Corners" issue, all of the corners in my drawing are less than 180 degrees and therefore inside corners. So with a "Less than" setting of 50 degrees, shouldn't the rule still only be applied to inside corners less than that angle. I mean is the overall meaning of the rule:
"On inside corners that have an angle less than 50 degrees" ??
The angle is how much the corner deviates from a straight line.

mancavedweller
Posts: 100
Joined: Tue Feb 25, 2014 6:53 am

Re: Path rule bug (on inside corners) ???

Post by mancavedweller » Mon May 20, 2019 12:57 am

Aah so that's how it works, thanks very much Les, I would never have guessed that. This info is getting archived.

Regarding the "On Arcs" rule being applied to outside corners, if say I had a 270 degree small arc in my drawing with internal kerf offset and I wanted to apply an On Arcs cut rule to that arc only. Let's say I wanted to turn THC off 5mm before the start of the arc and slow down feedrate 1mm before the start of the arc, then turn THC back on and put feedrate back to normal at the end of the arc.
I then find every outside corner has this rule applied and the feedrate slowdown affects the cuts on every outside corners, something I definitely would not want. It would be every outside corner because if the kerf width was say 2mm then taking into account the kerf offset from the drawing line, there'd be arcs 1mm in radius around the corners.

Also I can see many less knowledgeable users not understanding why the rule is being applied on corners, and think it's a bug. After all why is an arc rule being applied to corners. I myself thought it was a bug 2 days ago until I turned off the kerf width view and seen the tool path as an arc around the corner. Yes technically it is correct, but many users will not be thinking (or understand) about arcs in the tool path, their concern will be arcs in the drawing.

And in any case, we have a rule dedicated to outside corners.

Perhaps a simple solution would be an option tickbox in the On Arc dialogue to enable/disable the rule being applied to outside corners too.

Keith
Last edited by mancavedweller on Mon May 20, 2019 12:10 pm, edited 1 time in total.

User avatar
Les Newell
Site Admin
Posts: 2289
Joined: Thu May 11, 2006 8:12 pm

Re: Path rule bug (on inside corners) ???

Post by Les Newell » Mon May 20, 2019 11:44 am

I could add a 'exclude corner arcs' check box. That way older rule sets would still behave the same way as they always did until you select that check box.

mancavedweller
Posts: 100
Joined: Tue Feb 25, 2014 6:53 am

Re: Path rule bug (on inside corners) ???

Post by mancavedweller » Mon May 20, 2019 12:10 pm

Sounds great, thanks Les.

Keith.

mancavedweller
Posts: 100
Joined: Tue Feb 25, 2014 6:53 am

Re: Path rule bug (on inside corners) ???

Post by mancavedweller » Thu Jun 20, 2019 11:22 pm

Les Newell wrote:
Mon May 20, 2019 11:44 am
I could add a 'exclude corner arcs' check box. That way older rule sets would still behave the same way as they always did until you select that check box.
Les,

any rough idea on when you might get that tick box added. I have a big cut coming up where I have bend relief arcs and I wish to slow the feedrate at those arcs but don't want the rule being applied on any outside corners.

Cheers,

Keith.

User avatar
Les Newell
Site Admin
Posts: 2289
Joined: Thu May 11, 2006 8:12 pm

Re: Path rule bug (on inside corners) ???

Post by Les Newell » Fri Jun 21, 2019 3:51 pm

I'm hoping to have an update out in July. I'll try to add it to that update.

mancavedweller
Posts: 100
Joined: Tue Feb 25, 2014 6:53 am

Re: Path rule bug (on inside corners) ???

Post by mancavedweller » Mon Aug 19, 2019 6:34 am

Les Newell wrote:
Fri Jun 21, 2019 3:51 pm
I'm hoping to have an update out in July. I'll try to add it to that update.
Hi Les,

is the update still a while away.

Keith.

User avatar
Les Newell
Site Admin
Posts: 2289
Joined: Thu May 11, 2006 8:12 pm

Re: Path rule bug (on inside corners) ???

Post by Les Newell » Mon Aug 19, 2019 12:32 pm

Sorry about that. I have been having a few issues with my code signing certificate. As soon as that is sorted I'll upload an update.

mancavedweller
Posts: 100
Joined: Tue Feb 25, 2014 6:53 am

Re: Path rule bug (on inside corners) ???

Post by mancavedweller » Fri Sep 13, 2019 9:49 pm

Les Newell wrote:
Mon Aug 19, 2019 12:32 pm
Sorry about that. I have been having a few issues with my code signing certificate. As soon as that is sorted I'll upload an update.
Hi Les,

still some time away ?

Keith.

mancavedweller
Posts: 100
Joined: Tue Feb 25, 2014 6:53 am

Re: Path rule bug (on inside corners) ???

Post by mancavedweller » Fri Sep 20, 2019 11:10 am

Bump.......

User avatar
Les Newell
Site Admin
Posts: 2289
Joined: Thu May 11, 2006 8:12 pm

Re: Path rule bug (on inside corners) ???

Post by Les Newell » Fri Sep 20, 2019 11:40 am

Oops, sorry I thought I'd done that. It is ready for the next release.

Post Reply