Discussion Forum

Hi Luca

in V3.5a certanly there are different pick methods in 2D and 3D,
- in 2D the "box" method works readily.

- otherwise , in 2D and 3D you have the manual left right click, for group selection toggling, as well as CTRL-A (select al) and CTRL-D (DEselect all) I do not know of any "select complement" (PS: COMSOL developpers: could be a good idea, no ? ;) apart for the manual meshing commands.

- in 3D, by default you are in "no-select" mouse mode, you must deselect the "rotate" (Clockwise circular arrow, top of first icon column to the left of the graphic window) to allow "box selection", by choosing the "attention to": domains, subdomains, edges or points you also decide on which boundary/element you act upon.

Then when you have many items in complex 3D you may select (two red top icons, 2nd column to the left of the graphics view) take all or toggle items, that is when you select once along an edge close to a point, you get sequentially all, respectively each edge in a counterclockwise fashion. The same when you select in 3D an area with several clicks, you toggle each level from the wiewer down to the list item, along the line of sight.

You can also remove geometry from the window, unfortunately, you cannot reopen the "hidden box" and get back only one item, you must get back eveyone and then remove them one by one, or group by group again (PS: comsol developers: another hint for you ;)

When you have heavy models >500 edges etc, selection is difficult, you must play with the zoom and be very systematic, but the color scheme is helping too, make named groups as soon as possible (even if the group naming window becomes quickly very tiny !) it helps

So many ways out, hope it helps

Good luck
Ivar

Here is another trick that works very well with 3D geometries in combination with the methods Ivar outlined:

Orient your 3D object so that the lower order objects you want to select (points, edges, faces, subdomains) are all on one side. In addition to free rotate, zoom etc take advantage of the xy, yz or zx orientation tools on the right.
Here comes the trick. Now click the orbit/pan/zoom arrow (the clockwise curved arrow icon near the top of the icon list on the left hand side) to de-activate it. When you do this, you can draw a 2D box around the objects you want to select.
Downside: This is geometry dependent and doesn't work if the objects you want to select are not substantially located on one side in a given orientation. However, in combination with other methods this has saved me a lot of time by eliminating the need to select the objects one by one.

When you are done remember to activate the orbit/pan/zoom arrow again to recover the mouse default function in 3D modeling.
Good luck
Ozgur

I sometimes run into the same problem, especially with complex trusses.

As far as I know, there's no quick and simple way of doing it, but there are a couple ways to make it easier. Sadly, it seems like you can't select a subdomain in the subdomain mode and carry that selection to boundaries or edges (that would be a great feature).

As Ivan said, use (and abuse) groups. Normally, whenever I add geometry, I try to put it in groups as soon as I model them, and try to be very verbose about them.

Another good option is to use the boundary list in boundary settings. Get a feel of how COMSOL arranges them (basically, it starts at the origin and starts sweeping through the axes). Once you are comfortable with it, it can become a very powerful tool. It's been a lifesaver for me.

Hi Mario, I have some good news.

>Sadly, it seems like you can't select a subdomain in the subdomain mode and carry that selection to
>boundaries or edges (that would be a great feature).

We added this feature to version 4.0, to be released soon. A lot of other good stuff with repect to selection and model management has been added. Go to any of the COMSOL conferences if you want to know more and try it yourself.

www.comsol.com/conference2009/usa/

I sometimes run into the same problem, especially with complex trusses.

As far as I know, there's no quick and simple way of doing it, but there are a couple ways to make it easier. Sadly, it seems like you can't select a subdomain in the subdomain mode and carry that selection to boundaries or edges (that would be a great feature).

As Ivan said, use (and abuse) groups. Normally, whenever I add geometry, I try to put it in groups as soon as I model them, and try to be very verbose about them.

Another good option is to use the boundary list in boundary settings. Get a feel of how COMSOL arranges them (basically, it starts at the origin and starts sweeping through the axes). Once you are comfortable with it, it can become a very powerful tool. It's been a lifesaver for me.

Hi

good to hear that this picking feature is made more powerfull, this will be a timesaver for us with complex (true-life) models.

One more thing when having defined groups, I then have the edge, subdomain and domain properties GUI windows open most of the time, and by selecting the group names therein, you shitch directly the focus to the different elements, great for quick selection for postprocessing

Looking forward to learn more in Milano

Ivar

Hello Ivar
In part I solved my problems with boundary selection, and i found also other ways that, in my opinion are very useful, i have a geometry with more than 20 3D subdomains, so a lot of boundary and edges, to select quickly all interesting boundaries and assign them boundary cond, I hide all useless subdomains in subdomain mode, I move myself on the boundary mode and i select the boundaries without the jungle of other edges visible on the screen. Another way is 3 points procedure:
first: to save each subdomain in a different file
Second:to take all boundaries with a pick box without the fear to take also invisible boundaries, assign the boundary condition
Third: merge components
at the end when I merged all components I must reassign and check only the boundary conditions of a small quantity of boundaries.

Thank you
Luca