TUTORIAL 2 CAD CLEANUP AND AUTOMESH. Note: As in the other tutorials, all menu items that need to be selected will be preceded
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CAD CLEANUP AND AUTOMESH
by a maroon right arrow: >User action. Mouse buttons are indicated as follows: -- 1B = First (left) button -- used for selecting items-- 2B = Second (middle) button -- used for "OK"-- 3B = Third (right) button -- used for View Manipulation & pop-up menusNormally 1B is used, unless otherwise.Table Of Contents
Step1. Import Geometry from an IGES file. 3
Step2. Explore Geometry Graphics Display Options. 4
Step3. Use Stitch Surface Command.. 6
Step4. Extract Mid-Surface. 8
Step5. Suppress Entities .(Curves) 9
Step6 . Suppress Entities .(Vertices.) 10
Step7 . Force Suppression. 11
Step8 . Use of (Un)Suppress One Command. 13
Step9 . Trim Surfaces. 14
Step10. Use Auto Mesh. 16
Step11. Control Mesh Size And Shape. 17
Step12. Create Washer Elements Around Hole. 19
Step13. Create Hole On CAD Geometry. 21
Step14. Use Quality Check Command. 22
Step15. Use Enhance Quality Command. 23
(>Body Color, >Connectivity Color, >Part Color, and >Other Color).
Step3. Use Stitch Surface Command.
1. Select -> Type -> Part in Collection Menu.
2. Use (2B) to select > LEV_1-1 part.
LEV_1 appears next to "Curr:" at the top of CVP block.
(As you create new geometry and elements, they will go into the Current part.)
Part consists of a patchwork of small surfaces. Stitch
these surfaces together, with a user defined stitch
tolerance, to have a continuous part surface.
b. In order to clearly see the effects of the stitching operation:-
Select >Geom-Grafix -> Edge Color - >Conn.Color.
Select >Geom-Grafix >Faces Off.
to GREEN indicating that all the surface
patches got stitched and that the edges are shared
Step3. Use Stitch Surface Command.(Cont’d)
c. Turn ON:
Geom-Grafix >Boundary Edges
Geom-Grafix >Manifold Edges
Geom-Grafix >Suppressed Edge.
d. From Top Menu Bar
Select >Geometry >Stitch or
Click >Stitch icon from Toolbar
Pick menu > Sheet Bodies>click on >All button, at bottom of CVP block.
(The part gets highlighted in the canvas.)
g. Confirm the selection with >Done.
h. Enter the stitch tolerance (say 0.5) in the pop up panel, and confirm.
indicating them as boundary edges, now that the
top and bottom surfaces have been removed,
leaving only a single mid-surface .
Step4. Extract Mid-Surface.
Now let us extract the Mid-surface of the part.
a. Select >Geometry >Extract Surface. Or click Extract Surface >icon on toolbar.
(Note that the Pick menu at lower right changes to reflect the current command.)
b. Pick menu -> Select >Mid Surface and
Check the box for >Delete Solid.
(This will delete the solid geometry, upon completion of the Mid surface extraction. )
c. Select all displayed solid bodies:
Pick Menu >All and
Finalize the selection with >Done.
(Note that the mid surface of the part has been extracted.)
e. Select Geom-Grafix >Faces On.
f. Then, Click >View >FILL
to fill the part in the canvas.
g. Use ViewManip > DynamicRotation
and Zoom features to get a good look at the stitched midsurface of the part.
displayed now in BLUE color.
The manifold edges are highlighted
in GREEN color and
the boundary in RED color.
Step5. Suppress Entities .(Curves)
(Curves, those are not required for meshing of the part.)
a. For best viewing :-
1.Select >Geom-Grafix > turn >Faces Off.
2.View back to >Right-Frt.
b. Select >Geometry>(Un)Suppress Entity or Click >(Un)Suppress Many icon.
c. On Pick menu -> Select >Curves
d. Select >B.A in the Pick panel.
e. Enter > 15 degrees in the popup panel ,confirm
f. Select > All from Pick Block.
g. Confirm with >D (Done) at bottom of Pick block.
(Vertices, those are not required for meshing of the part.)
View Manip. >Window Zoom
to obtain a view like the picture shown.
c. Check the box for >Force Suppression and
d. Select > Curves from the Pick block.
e. Select View Manip. > Window Zoom
f. Select >curves that are to be suppressed.
g. Then while the mouse is still in the canvas, click the middle mouse button. (>2B) or
Click >D button at bottom of Pick Block.
Now try picking curves by refine pick option.
Do not close the "Extended Pick Dialog" window until completing the next step.
e. Pick curves by selecting on the >vertex which joinsthree curves as shown in fig.
f. This allows selection of multiple curves which share a given vertex.
g. Repeat for 2nd set of curves.
h. Confirm the selected curves with >(2B).
i. The forced suppressed curves are now shown in BLUE.
j. Exit out of the Suppress Entity command by clicking >Ex (Exit) at bottom right corner .
Let's try a similar command that takes advantage of
(Note how this command is a bit different from (Un)Suppress Many command.)
e. This is a toggle command and entities are immediately suppressedupon picking them.
f. If selected again, the entities will be returned to Un-suppressed state.
g. Also note that any symmetrical entities are also suppressed on the other side of the part.
h. Rotate the model >View.Manip >Dyn.Rot to get a clear view of the other end of the part.
i. Pick curves to be suppressed on the other end of the model.
to remove suppress edges from display.
b. Set >Suppressed Points >Off.
c. Zoom and rotate the model to obtain the view shown.
d. Select >Geometry >Trim Surface By Locs (or select icon from toolbar)
e. Pick entity type of Vertices (default).
f. Trim the geometry by selecting end point >vertices defining the new curve to be placed on the surface.
g. Confirm with >2B to complete the trim operation.
h. In a similar fashion, trim the surface at a second location.
j. Return to >Geometry >(Un)Supress Entity to suppress the original small
k. Rotate the model, then trim and suppress curves at the other end of the model in a similar fashion.
l. Set >Geom-Grafix >Boundary Edges On
Geom-Grafix >Manifold Edges On
Geom-Grafix >Face Color >Part Color
Geom-Grafix >Edge Color >Connectivity Color
The geometry is now cleaned up and ready for meshing.
Save the model as MSC.SOFY database >File >Save As >...\Bracketclean.sof
Pick >Automesh icon from Mesh toolbar.
MSC.SOFY can automatically decide the best meshing method based on geometry. in Pick panel.
c. In Pick Panel
Select >Auto Decide
Select >Mixed (Quad Dominant) in Pick panel.
Select >Surfaces to be meshed.
d. In this case select >All to mesh all displayed surfaces in the canvas.
e. Confirm with >D (Done).
g. Select >Geom-Grafix >Face Off
and zooming into the model
for a visual inspection.
Let us take a closer look at mesh quality and update the mesh
by making certain changes in the Mesh controls.
zoom in to the small hole in the foreground (left side of part).
1. Select>curve that defines the hole.
2. Confirm with <(2B).
3. Then in the pop-up menu,
"Enter # Segments:" 4, then >OK.
i. Notice that any part of the mesh that is affected by the revised number of segments around the hole, is immediately removed from the display.
j. Select >Mesh Menu >Update Mesh.
Notice the revised element distribution around the hole.
>ViewManip.>Dyn.Rot to get a good look at the slotted hole at the other end of the model.
n. Set >Geom-Grafix >Hard Points ON.
>Geom-Grafix >MeshPoints ON.
o. Now create a hard point on the hole to seed the nodes in a desired fashion:
1. Select >Geometry >Create Hard Points.
2. Select >Pt. on Curve from pick menu.
3. Select >curve that defines the hole followed by a >new point on the curve.
4. For instance select a point on the hole nearest the edge of the part.
5. Click >Exit button in Pick block.
p. To redefine the number of points around the elliptical hole:
1. Select >Mesh Menu >Mesh Size, or Mesh Size icon.
2. Pick menu> Curve (Entity type ).
3. Select the hole edge.
4. Confirm the selection with >(2B).
5. Enter # Segments >6 and >OK, on the pop up menu .
Select >Mesh Menu >Update Mesh.
Later on we will make some further improvements to the mesh quality.
Now let us look at a quick way to create a washer around a
to zoom in on the hole on the top of the part, where we will create a washer (concentric rings of elements).
c. Toolbar> Geometry Cleanup menu >Create Washer icon.
d. On canvas, Select >curve at the hole where washer is desired.
e. Confirm with >(2B).
f. Enter width (say 5 mm) of the washer in the pop up menu.
Choose the newly created >washer curve.
k. Click >Ex at lower right corner to exit the Link Curves command.
By linking the curves, the mesh quality is better controlled.
l. Select >Mesh Size icon from Toolbar.
m. Pick Menu > Curves is highlighted
n. Select >hole from the canvas.
o. Confirm curve selection with >(2B).
p. In the pop up menu,
1. Enter # Segments: 6.
2. Click >OK.
a. Set >View >Left-Frt. and Zoom in to corner where hole is to be placed.
b. Select >Mesh Menu >Create Hole (or select icon from Toolbar).
f. Confirm with (2B).
g. Enter the radius of the hole (say 12 mm) in the pop up menu.
h. Select >Mesh Menu >Mesh Size to define number of nodes on the hole, as done above.
If desired, create a curve defining a washer around the hole, and link the two curves, as above.
i. Select >Mesh Menu >Update Mesh
(or select icon)
to recreate the mesh .
j. >Exit any active commands,
k. Click >F4 key to clear
the unreferenced nodes.
Now let us check and Enhance the Quality of the mesh.
d. Pink color indicates the elements that failed in one or more quality checks.
Detailed Quality checks
and Automatic Mesh Quality
Enhancement are discussed in Tutorial 5.
Time for a break.!!!!