extract geometry

[thixoguy]

Hi All,

I have a few questions regarding the "extract geometry" feature.

1. What is the difference between "extract" and "multiple extract"? I have read the documentation but I just can't seem to get my head around it. Would someone care to enlighten me?

2. In UG there exists "extract geometry" with an "extract region" sub option that allows you to to essentially extract a region of surfaces by picking one internal surface and then picking a series of boundary surfaces. The system then automatically selects all the surfaces in between the first surface you pick and the boundary surfaces. Is there a way to achieve similar results in Catia? I have played around with the different propagation types but in the end I either get too many surfaces(point continuity) or I spend a lot of time picking individual surfaces( no propogation). Is what I am trying to achieve even possible in Catia, and if so, how should I go about it?

Thanks in advance, thixoguy

 

[kaesar]

Hi,
1. There is no difference between "extract" and "multiple extract", "multiple extract" is for make more than one extract at the same time.

2. In Catia it doesn’t exist, my recommendation is to take the limit boundary with the join command and trim the surface with it.

 

[DBezaire]

Thixoguy - Multiple Extract is a glorified extract. With extract you can select the various propogation methods, but this will apply to all the surfaces you select. If I select 10 surfaces and the continuity is set to tangent the results might be 10 seperate patches of tangent data. With mult extract you can select 10 surfaces with different continuity types.
Have you checked out the complimentary toggle.
We use extract to seperate core/cavity data. For the most part we can achieve the desired results with the use of tangency and complimentary during extraction. We have 3 systems with CCV - most parts we receive can be split with these methods.

Regards,
Derek

 

[DBezaire]

I forgot - that functionality in UG does not exist in Catia. You could achieve a similar result. Create a sketch, make an extrusion with the closed sketch. Trim back the surface data with the extrusion - then use the extraction methods.

Regards,
Derek

 

[thixoguy]

DBezaire,
Though I prefer the UG extract region, your workaround is an excellent method. Thank you

kaesar,
Is your workaround the same as DBezaire's? If it is, a big thank you to you as well, if not, could you please elaborate?

thixoguy

 

[kaesar]

hi thixoguy,
my recommendation is to take de limit boundary of surfaces you want to extract and trim the total surface with this boundary. You can get this limit boundary with the join command. The join command lets you to take and join internal boundaries of surfaces.
I think this method is the same as the UG extract region but in steps, 2 steps.

Luck

 

[DBezaire]

thixoguy - kaesar's method is vary similar, he/she takes the time to pick the curves to trim back to. I guess it all depends on what you are looking to achieve.

Regards,
Derek

 

[jmuriarte]

Hello:

Is there any way to multiselect faces with point or tangency continuity? For example if I want to bring surfaces from an Iges and I need select the upper skin of a sheet metal part.

Thanks

 

[kaesar]

jmuriarte,
if you take surfaces from an iges model yoo have to join all of them first. After that the way for selecting faces with point or tangency continuity is with the extract command, but if you choose the point continuity option you will extract all surfaces (the same as the first join).

 

[DBezaire]

jmuriarte - when you join your surfaces you have 2 additional options in the contextual menu. Select a surface - contextual menu inside the element to join area. Angular and distance propogation. If you leave the datum on - create a new geometric set (for our example "A")- create the join with appropriate propogation method. Now change the geometric set of the join (I realize it is already in the new set) to set "A" and choose the move parents option.

Regards,
Derek