Create a net surface

[skyking01x]

This problem I have is a real PITA and I'm not sure it's me or MCX9.  When creating a net surface with different or any type of entities for each 'along' or 'across' grid members it takes me way to long to create the surface.  On a given 'along' member I will get "Partial chain: Path between first and last entities not found".  I check the chain with "Analyze/chain" and it says the chain is fine, no overlaps, etc. but when I try to create an 'along' member in "Net surface" is gives the error!  I don't understand why the chain checks ok in one function and coughs in the other.  This isn't complicated! WTF!  What am I doing wrong?  I'm thinking the chain tolerances are too tight and not adjustable in Create/Surface/Net while checking good in Analyze/Chain.  Help?

 

[Guest]

Sight unseen as there's no file....

 

It's possible that this is a job for a coons surface

 

Just a WAG at this point though

[Guest]

Coons rules! :

[mkd]

...And the classic; entities at different Z levels, thus not actually touching

[skyking01x]

OK, I guess I don't the difference between a Coons surface and a "Net" surface.  I thought "Net" was the X9 renaming of "Coons".

[skyking01x]

*know*

[Guest]

ALT + C

 

you'll find coons

[Thad]

OK, I guess I don't the difference between a Coons surface and a "Net" surface.  I thought "Net" was the X9 renaming of "Coons".

 

They're kinda sorta the same, but it goes back way farther than X9. Version X (version 10, which is 9 versions prior to X9) maybe?

 

Coons surface all the way!

[skyking01x]

I can't post my drawing but I had a simple, one panel Net surface.  i.e. two alongs and two acrosses.  One along was 5 simple straight line segments and the other along was a single straight line.  The acrosses were simple single arcs all creating a crazy, corner surface.  The 5 segment along would not work, always the partial chain error.  Yet under analyze/chain a perfect 5 segment chain was shown.  This happens to me at some level whenever I try to create a semi-complex net surface.  So, you guys are telling me that the Coons C-hook won't do this?  I seem to remember the same issue with older versions of MC which supposedly had the C-hook Coons routine only.

[Thad]

Can you share just the geometry (4 chains) that you're trying to create a surface from? Otherwise, we can speculate and talk about it all week and still not accomplish anything.

[Müřlıń®]

"One along was 5 simple straight line segments"

 "I'm not sure it's me or MCX9. "

 

 

Definitely operator error..

Net is seeing one of the intersections of the 5 lines as a corner and does not know what to do.

 

Break the single line into 5 along segments also and use sync.

 

Net does it's best to create nice tangent surface patches...

 

Coons will patch just about any set of entities as long as they will sync

but it will have stretchy bumpy results depending 

on the geometry.

[skyking01x]

Thank you Murlin for your lucid explanation!  Now I see why analyze/chain doesn't agree with surface/net.  I did solve my own problem by adding small radii at each of the 4 intersections of the 5 segments but that wasn't the real question.  Thanks to everybody else for your inputs.

[Müřlıń®]

Thank you Murlin for your lucid explanation!  Now I see why analyze/chain doesn't agree with surface/net.  I did solve my own problem by adding small radii at each of the 4 intersections of the 5 segments but that wasn't the real question.  Thanks to everybody else for your inputs.

I used to have the same problem with NET until I finally figured it out.....I have also fixed it the same way you did,,,

Either way will work but if you want to make a watertight solid out of some surfaces and you are patching

with NET, you will need to use the break method.

 

I started surface modeling with Coons before NET was even made and Coons forced you to sync and wouldn't work with unequal number entities in a chain..

 

So it was easier to figure out what was wrong when Net came along...

[Guest]

I used to have the same problem with NET until I finally figured it out.....I have also fixed it the same way you did,,,

Either way will work but if you want to make a watertight solid out of some surfaces and you are patching

with NET, you will need to use the break method.

 

I started surface modeling with Coons before NET was even made and Coons forced you to sync and wouldn't work with unequal number entities in a chain..

 

So it was easier to figure out what was wrong when Net came along...

 

Morlin , you actually CAM use unequal entities in chains. How else could you create a coons patch from 3 entities? You can use an endpoint as an entity.

 

Been using Coons since probably 1995. There are few functions in Mastercam that I would consider myself an expert, coons is one of them. Netsurf is ok but Coons, while a little harder to use on the surface is still better. The hardest thing about it is getting your "method" down. I have a method I've used for close to 20 years now and it just works.

 

 

Here's a demo I put together a while bacak that explains things. A video and a file.

https://www.dropbox.com/s/udabgvy1a38ne6q/Build%20Coons%20Surface.wmv?dl=0

https://www.dropbox.com/s/0irnntwyll67td5/CoonsPatch_WireframeAndSurface.mcam?dl=0

[Fred @ Slate Industries]

Nice Result ,

Going the extra mile on chaining and proper technique...

[Guest]

Nice Result ,

Going the extra mile on chaining and proper technique...

 

When I taught Mastercam, we went over it extensively. Everyone had to do a crazy part I had and create a single surface out of it. I didn't make them create the wireframe, just the single surface patch. It took two class sessions for them to get it down.

[Müřlıń®]

Morlin , you actually CAM use unequal entities in chains. How else could you create a coons patch from 3 entities? You can use an endpoint as an entity.

 

 

 

 

On the 3 sided corner in your example, you still have 2 nodes in the across #1 and 2 nodes in the across #2(an equal number)...... you just share a node 

I guess it is all in how you look at it.  So ya I should have said nodes instead of entities...forgot about sharing a point...U da man.

 

I don't use Coons anymore except when I want a Flowline to output a better path...(I believe you showed me that trick too )

other than that Net makes much better surfaces to create solids from than Coons..

 

 

 

Very cool video BTW...

[#Rekd™]

Awesome video James!!! :unworthy:

 

Why do you need to select points in the first row?

[Matthew Hajicek - Singularity]

My first job after tech school I was using Coons for guitar necks:

 

http://olsonguitars.com/the-artisan/jims-shop/the-fadal/

[Guest]

Awesome video James!!! :unworthy:

 

Why do you need to select points in the first row?

Thank you.

 

A Coons Surface needs to be bound by 4 chains. Those chains can be a single point or they can be a number of entities.

 

NetSurf probably does better for solid creation because of the UV surface direction (just a guess).

[Guest]

On the 3 sided corner in your example, you still have 2 nodes in the across #1 and 2 nodes in the along #2(an equal number)...... you just share a node

Fiss and, I could have broken up the 3 entity corner to have unequal numbers of entities and just make sure I chain them in the right order amd.correctly with NO sync and end result would have been the same. :

[Müřlıń®]

Fiss and, I could have broken up the 3 entity corner to have unequal numbers of entities and just make sure I chain them in the right order amd.correctly with NO sync and end result would have been the same. :

ok help me out here cause I am having trouble making it work....

 

1 across

1 along

 

make a coons

 

 

 

I get this no matter what I try.

 

[Matthew Hajicek - Singularity]

Make sure your chaining direction (start end) is going from 1 to 2.  So along 1 and 2 should start at across 1 and end at across 2, and across 1 and 2 should start at along 1 and end at along 2.

[crazy^millman]

Here is what I did with something similar to the shape you put up Murlin. I broke up my chains and on the Radius example I made the length of the line the same as the length of the arc.

 

https://www.dropbox.com/s/2n4s87a1i3suk9z/5th%20Axis%20Coons%20and%20Net%20Example.mcam?dl=0

[Guest]

Shoot me that geometry Murlin.