Some MeshVS commands not supported in Draw Test Harness

Mowei Wang
Sun, 06/12/2022 - 17:45

Forums:

When testing MeshVS (Mesh Visualization Service) component with Draw Test Harness, I find meshdispmode command and meshselmode command are not supported. However, both commands are listed in occt_test_harness.pdf.

I searched a very old topic which was similar to my concern. It seemed meshselmode command was supported before.
https://dev.opencascade.org/content/selecting-nodes-elements-mesh

Why these two commands are deleted in latest OCCT?

Attachments:

meshvs-commands.png

Kirill Gavrilov
Sun, 06/12/2022 - 21:56

MeshVS_Mesh inherits AIS_InteractiveObject so that most of general-purpose commands from ViewerTest plugin are applicable to mesh objects as well. This includes commands "vselmode" and "vsetdispmode" managing active display and selection modes.

Mowei Wang
Mon, 06/13/2022 - 05:56

Hello Kirill,

Thank you. "vselmode" command targets geometry entities, not including mesh entities. I guess it'll be not very difficult to add mesh selection modes to "vselmode" command.

Another question, when "4 - face" selection mode is chosen for "vselmode" command, only the surface visible faces can be selected. How to select the faces behind the scene with click-selection or box-selection?

Attachments:

face-is-visible.png

face-not-selectable.png

Kirill Gavrilov
Mon, 06/13/2022 - 09:19

4=face is only for AIS_Shape presentations. Each interactive object defines it's own list of selection modes - so you would need checking documentation of MeshVS_Mesh as a C++ class. It defines selection modes not as a list, but rather a bitmask MeshVS_SelectionModeFlags:

typedef enum
{
  MeshVS_SMF_Mesh    = 0x0000,
  MeshVS_SMF_Node    = 0x0001,
  MeshVS_SMF_0D      = 0x0002,
  MeshVS_SMF_Link    = 0x0004,
  MeshVS_SMF_Face    = 0x0008,
  MeshVS_SMF_Volume  = 0x0010,

  MeshVS_SMF_Element = MeshVS_SMF_0D | MeshVS_SMF_Link | MeshVS_SMF_Face | MeshVS_SMF_Volume,
  MeshVS_SMF_All     = MeshVS_SMF_Element | MeshVS_SMF_Node,

  MeshVS_SMF_Group   = 0x0100

} MeshVS_SelectionModeFlags;

pload XDE VISUALIZATION
vinit View1
meshfromstl m [locate_data_file bearing.stl]
vfit
# MeshVS_DMF_Shading = 0x0002
vsetdispmode m 2
# MeshVS_SMF_Face    = 0x0008
vselmode m 8 1

vmoveto 200 200
vstate -entities

Point detection returns a list of entities through picking ray sorted from closest to farthest, and on click the topmost element is selected from this list.

Mowei Wang
Mon, 06/13/2022 - 12:01

Yes, well done. It also supplies "-add" and "-set" option.

# Both nodes and surface elements can be selected
vselmode s -add 1 1
vselmode s -add 8 1
# First node selection, then surface element selection
vselmode s -set 1 1
vselmode s -set 8 1

BTW, how to get the ID of the topmost element for click-selection? And how to get a list of IDs for box-selection?

Kirill Gavrilov
Sun, 06/12/2022 - 22:18

Why these two commands are deleted in latest OCCT?

"Latest" is a little bit imprecise here. From git log it seems this change was done almost 8 years ago, and released in OCCT 6.8.0.

Mowei Wang
Mon, 06/13/2022 - 06:01

Thank your for correcting my misunderstandings. I'll check the older OCCT releases and try to find the implementation of "meshselmode" command.