Hi! When I spilt a complex volume(real) with a real face,GAMBIT appears the following messages : ERROR:ACIS error 8030:decision to delete intersection graph was incorrect Restoring the geometric model to the state before the current operation(if there is a positive number of default UNDO levels).

What's going wrong with it?Please help me!

You'd better regenerate the face and volume,sometimes it behaves as if the faces or volumes are virtual. I came across with such situation many times,but after I redrew the shapes , it did not occur again.

what i found is when we are dealing with complex shapes or the volumes with many operation already done , i am getting this problem. I also found this problem when i have done binary operations on the volume of intrest with the volume imported from cad model (iges format)

[bigphil]

Originally Posted by Tmr
;137807

You'd better regenerate the face and volume,sometimes it behaves as if the faces or volumes are virtual. I came across with such situation many times,but after I redrew the shapes , it did not occur again.

Hi Tmr,

I am having the same problem.

What do you mean by regenerate?

Best Regards,
Philip



EDIT: I realised if I heal the geometry, then I no longer get the error.

[-mAx-]

delete the face, but disable the lower geometry option (it will delete the face but not the attached edges)
Then recreate the face with wireframe (choose the attached edges)
I think it is what he means

[bigphil]

Thanks mAx.

[George Chen 28]

Hi, pals.
I got a problem with Gambit. I generate a real volume and creat several virtual edges hosted on the face of the real volume. then I use the wire framed virtual face to split the real volume. Error occures-------"Attempted to split volume.1 using face v_face.8 that doesn't divide it into two parts (has edges no common with the volume)".
I have no way to cope it. hope somebody to help me. thank you anyway.

[-mAx-]

With virtual entities, your edges should belong to the surface. I mean they must split your surface.

[George Chen 28]

Originally Posted by -mAx-

With virtual entities, your edges should belong to the surface. I mean they must split your surface.

sorry, mAx. I don't know what you mean. Does "your egde" refer to the virtual edge? if so, I created them hosted on the real faces of the real volume.

operations or logic involved in virtual entities are always confusing. My throughts about it are always wrong. it makes me sick！

[-mAx-]

if you want to split a volume, you have to split it with a surface.
With virtual entities, the edges of this split-surface has to belong to the volume you want to split.
For instance if want to split a cylinder (z-extrusion), you have to split the covering (not the caps) at a certain z-coordnate. The split generates a circle which divides the covering into 2 coverings (cylinder is now mad from 2 caps and 2 coverings). Then create a surface from this circle, and split the volume with this surface.
What I meant, is that the circle belongs to volume (prior to split operation). At the opposite, with real entities, you can create a (xy)-plane at the same z coordinate, and split it on the fly. (but here the plane doesn't belong to the cylinder)
I hope I was clear

[George Chen 28]

very clear, mAx. thank you very much.
I will try tomorrow and let you know if it work.

[George Chen 28]

Yeah, mAx, I have split a real cylinder into three virtual cylinders by the method you told me. I would like to have your favor of checking my operation.
I create two xy-planes at the different z coordinate. Then I split the covering into three real faces using both, so it generates two circles on the covering of the real cylinder. I create two virtual faces using both circles respectively. Finally I split the real cylinder into two virtual cylinders using one of the two virtual faces and then split one of the virtual cylinders using the other virtual face. I get three virtual cylinders in the last place!
Is my operation the best choice for my purpose？It is too delicate to do correctly, I think.
I don’t need to specify the boundary type for any virtual face, am I right?
It will not happen that there is non-conformal grid on the virtual face which is shared by two virtual volumes. Is the assumption right?
Sorry for bothering you so much. I am new to CFD.
Thank you!

[-mAx-]

*well what you did is correct, but you are handling a real volume, so you could directly split the volume with plane (without splitting any surfaces, thus this operation is implemented for real entities). If your initial cylinder was a virtual one you couldn't split the covering with the plane, I post at the end the journal file for splitting the cylinder without any plane
You can open a gambit session and read this journal (*.jou), enable "Step" option, to observe step by step the split
*the split surface should appear in pink (connected) if you enable the connectivity modus (icon right from the examine mes icon). Per default, the split surfaces are set as interior, but won't appear as BC

*JOURNAL:
----------
volume create height 10 radius1 2 radius2 2 radius3 2 offset 0 0 5 zaxis frustum
default set "GRAPHICS.GENERAL.CONNECTIVITY_BASED_COLORING" numeric 0
edge split "edge.2" percentarclength 0.5 virtual
edge split "edge.1" percentarclength 0.5 virtual
face split "v_face.4" vertices "vertex.2" "vertex.1"
face split "v_face.7" vertices "v_vertex.3" "v_vertex.4"
edge split "v_edge.7" percentarclength 0.5 virtual
edge split "v_edge.8" percentarclength 0.5 virtual
face split "v_face.8" vertices "v_vertex.5" "v_vertex.6" bisectangle
face split "v_face.9" vertices "v_vertex.5" "v_vertex.6" bisectangle
face create wireframe "v_edge.14" "v_edge.13" virtual
volume split "v_volume.2" faces "v_face.15" virtual
default set "GRAPHICS.GENERAL.CONNECTIVITY_BASED_COLORING" numeric 1

[George Chen 28]

Yes, mAx, your are right. “If your initial cylinder was a virtual one you couldn't split the covering with the plane”. So I create two circles on the covering at different z-coordinates in advance. Then at the second split of volume, I could use one of them to create a virtual face and then split one of the two virtual cylinders generated by the first split of the real cylinder. I realize that operations to a virtual volume are very restrictive. I can’t use a plane to split the covering of the virtual volume although the covering is a real face.

Please email me the jou file you mentioned, because I copied above code and created a jou file. It doesn’t work. In gambit TUI, it showed “syntax error”. I am not able to rectify it. So please give me a complete file through e-mail.

My email address is chenfrigate@yahoo.com.cn. Thanks for your help. It is very precious to me.

[-mAx-]

I am not sure what you did can be successfull because the circles you created don't belong to the covering (not connected), and that is the problem with virtual entities

I copied what I posted into a file, called blabla.jou and read it from gambit. It works from my side.
Anyway, what I did:
*create a cylinder z-oriented , with whatever you want as length and radius
*split each cap's edge (circle) with location ratio 0.5 (it generates another vertex on the circle)
*split the covering face with the 2 originals caps vertex (it generates a generatrice parallel to z on covering)
*do the same with the 2 other vertex
*split each generatrices with location 0.5 (it generates a vertex in the middle)
*split each covering with those 2 points (enable sharped edge) --> it generates 2 semi-circle (here the coverings are splitted, and the split circle is connected to the covering--> that's the difference)
*create surface from the 2 semi-circles
*split the cylinder with this surface
--> that's it