Problem with AOVLAP,,,,Help 1

[nodalDOF]

Is there a way to select only the newely resulting areas from the boolean operation AOVLAP. The problem here is the output areas also includes some of the input areas.

Ex: Input areas: 1 2 3 4 5
OutputAreas: 3 6 7 8 9 10 11

After the operation all the areas (1:11) will remain selected and you dont know the only output areas.

I used BOPTN to delete input areas, but is didnt work as the input areas are attached to some volumes. I also tried to store the numbers of areas but no success as we dont know whether the resulting areas might include one of the input areas too.

 

[TGS4]

Store the existing areas in a component (CM command). Then, unselect the component afterwards (CMSEL command).

Trust me, components are your friend. Once you learn to work with them, you won't be able to figure out how you worked without them.

Good luck. BTW good question and it was well-posed.

 

[nodalDOF]

TGS4, thanks for reply. However, i think its not that simple. Take a look at my question. Suppose initially if you group the input areas (1,2,3,4,5) as one set (cmsel,,set1,AREA) and after the OVLAP operation as set2 that includes areas 1:11 and now if you unselect set1 you will have the areas 6:11 and the output area 3 (That is also an input area) will be missing. Its interesting that i never faced this problem until today.

nodal

 

[TGS4]

Ah - I see your problem.... So area 3 is not modified. Hmmm...

Why would you be performing boolean operations on areas that are already attached to volumes?

 

[nodalDOF]

Those volumes were imported from xyz CAD software and are not good for mapped meshing. However we can use the areas to mesh and extrude that makes my life easier.

 

[JaStKn]

Hi!

1.)If you use

numstr,area,arinqr(0,14)+1

the resulting area numbers beginning with the maximum area number plus one.

2.) New areas have none attributes. If you give the input (unmeshed) areas an attribute (real,mat,type,esys or secn) with the aatt command, the new area attributes are blank.
So you can select after the boolean operations all areas with blank attributes. For example asel,s,real,,0.

Olso I think, you can save all lines of input area in a component. After the boolean operation you can select these areas witch are attached completle on this lines. asel,inve will give you the new areas.

asel,s,,,1,5
lsla,s
cm,line_save,line

!boolean operation

cmsel,s,line_save
asll,s,1

asel,inve

cm,new_areas,area

)

Hope this is OK for you .... Stefan.

 

[nodalDOF]

Hi JaStKn/Stefa,


Thankyou very much for your suggestions. I have tried all you ideas but no success still. However, you deserve a star and you got it.

FYI here are the problems associated with each of your ideas.

My actual geometry input/output areas: (Original posting was just framed to illustrate my problem)

AOVLAP displays following output

Input areas : 120, 121 ,122 ,123 ,124, 125
Output areas: 124, 1300, 1301, 1302, 1303, 1304, 1305, 1306

(1) numstr,area,arinqr(0,14)+1

The resulting areas did begin with Max area number+1, but the unmodified area (124) is still there in my output areas.

(2) Attribute assignment

Same problem as above. The unmodifies area (124) is still having the given atttribute and got unselected when i selected areas with blank attributes.

(3) Line selection.

The unmodified areas got unselected by "asel,inve,". Also it selected many unwanted areas in my model (1:120)

In brief the unmodified area/s are the reason behind this problem. Also, the reason for this area/s not being modified is, it is totally within the domain of other input areas.

I wish ANSYS has a command to select/unselect areas resulting from boolean operations.

Thanks
nodalDOF.

 

[nodalDOF]

If someone is intersted in this problem, check with sample file illustrating above discussion...

finish
/clear
/prep7

blc4,0,0,10,10,10
wpoffs,5,10,5
wprot,0,-90,0
cyl4,0,0,2.5,360,5,360,10
asel,s,loc,y,10 ! selects areas 4,7
aplo
aovlap,all !Input :4,7 Output areas: 7,13,14,15,16,17

finish

thanks
Nodal....

 

[JaStKn]

It must be work!

alls
cm,atmp,area

asel,s,,,1,5
cm,a_save,area

aatt,,100

aovlap,all

asel,s,real,,100
cmsel,r,a_save !-> unmodified input areas
asel,inve
cmsel,u,atmp !-> new areas


May be ANSYS destroy components during the boolean operation. hmmm. There is an other way to save areas.

Do you know something about vector operations in ANSYS?

OK:

! 0.) selection of areas

! 1.) Define a vector:

inp=
*dim,inp,array,arinqr(0,14),1 !Length of vector = maximum area number

! 2.) Save the selection status of (input) areas in column 1
! of vector [inp]

*vget,inp(1,1),area,,asel

! 3.) boolean operation

! 4.) Save the selection status of (ouptut) areas in column
! 1 of vector [outp]

outp=
*dim,outp,array,arinqr(0,14),3
*vget,outp(1,1),area,,asel !selection status

! 5.) compare selection status of areas bevore and after
! boolean operation

*vmask,inp(1,1) !Masking vector
*voper,outp(1,2),inp(1,1),eq,outp(1,1) !unmodified areas
!new areas ->
*vmask,outp(1,1)
*voper,outp(1,3),outp(1,1),ne,inp(1,1)

! 6.) select unmodfied areas

asel,none
*vmask,outp(1,2)
*vput,outp(1,2),area,,asel

cm,unmod,area

! 7.) select new areas

asel,none
*vmask,outp(1,3)
*vput,outp(1,3),area,,asel

cm,new,area

I have my ANSYS not here so it can be a error in my code. But normaly it must work.

.... Stefan.

 

[nodalDOF]

Stefan..Thanks again. Still no success. Good thing is I have learned a lot from your suggestions. Spent considerable amout of time understanding your vector operations. Never used them before. Very Very useful!

Thanks
NodalDOF.

FYI following is the input i am using......

-----------------Case 1-----------------------------------------------------------------------
finish
/clear
/prep7
blc4,0,0,10,10,10
wpoffs,5,10,5
wprot,0,-90,0
cyl4,0,0,2.5,360,5,360,10
allsel $cm,atmp,area
asel,s,loc,y,10 ! selects areas 4,7
cm,a_save,area
aatt,,100
aplo
aovlap,all ! Input: 4,7 Output: 7,13,14,15,16,17
asel,s,real,,100
cmsel,r,a_save ! I think this one is redundant....nothing changes
asel,inve
cmsel,u,atmp
aplo ! Remaining : 13,14,15,16,17 (7 is missing )


----------------Case 2----------------------------------------------------------------------
finish
/clear
/prep7
blc4,0,0,10,10,10
wpoffs,5,10,5
wprot,0,-90,0
cyl4,0,0,2.5,360,5,360,10
allsel
asel,s,loc,y,10 ! selects areas 4,7

*dim,inp,array,arinqr(0,14),1 !Length of vector = maximum area number
*vget,inp(1,1),area,,asel
aovlap,all ! Input: 4,7 Output: 7,13,14,15,16,17
*dim,outp,array,arinqr(0,14),3
*vget,outp(1,1),area,,asel !selection status
*vmask,inp(1,1) !Masking vector
*voper,outp(1,2),inp(1,1),eq,outp(1,1) !unmodified areas
*vmask,outp(1,1)
*voper,outp(1,3),outp(1,1),ne,inp(1,1)
asel,none
*vmask,outp(1,2)
*vput,outp(1,2),area,,asel
cm,unmod,area
asel,none
*vmask,outp(1,3)
*vput,outp(1,3),area,,asel
aplo ! Again AREA 7 missing (13,14,15,16,17 selected)
--------------------------------------------------------------------------------------------------------------

We need a way to differentiate between the areas 4 (Present in input but not required in output) and 7 (Required in outpurt), both of whose status remains selected after the boolean operation.

 

[JaStKn]

Ok.

What you are trying can't work.
Area 4 belongs to volume 1 and area 7 to volume 2.

What you need is the vglue command.

finish
/clear
/prep7
blc4,0,0,10,10,10
wpoffs,5,10,5
wprot,0,-90,0
cyl4,0,0,2.5,360,5,360,10
allsel

vglue,all

ready )

But attention!

You get some bad (peaked) areas for meshing in your example. Hope this is not a real geometry!
I connect such parts with bonded contact!

Why do you do'nt use the ANSYS Design Modeller for geometry import? He is more powerful then ANSYS Classic (Also in boolean operations!). If geometry import / modification is ready you can go to ANSYS Classic by exporting a ANSYS *.anf file for example or simulate the problem in ANSYS Workbench. (ANSYS Workbench can find contact regions automatically)

Best Regards .... Stefan.

 

[nodalDOF]

Thanks Stefan. That works. I dont need those volumes later anyway. Also for now i think i should just be satified with the ANSYS displaying input and output areas list atleast during the boolean operations. Probably the guys who developed those commands did think about it...

thanks
nodal....