Tips

How to Mesh a Partial Sphere

The trick is to subdivide the model to create three sweepable volumes. This is done by cutting a cylinder through the top of the sphere and splitting the outer volume in half.

Video

Parial Sphere

Journal File

Note: The following Trelis commands can be pasted and played in a journal file.

Method One

#Begin by creating a partial sphere
reset
create sphere radius 10 ypositive

#Create a cylinder that will be able to fit in the center of the sphere
create Cylinder height 20 radius 5

#Rotate the cylinder
rotate Volume 2 angle 90 about X include_merged

#Webcut and delete the cylinder
webcut volume 1 with sheet extended from surface 3
delete Volume 2

#This next webcut makes the partial sphere sweepable
webcut volume 1 with plane xplane offset 0 noimprint nomerge

#Mesh
imprint all
merge all
mesh vol all

#Check mesh quality
quality volume all shape global draw mesh

Method Two

Another method is to mesh a full sphere, put half the elements in a block, and then export only half of the sphere. Then, you can import the half sphere.

reset
sphere rad 10
Vol 1 scheme sphere
mesh vol 1

block 2 hex in node with x_coord > 0.3
draw block 2

export mesh "test1.e" dimension 3 block 2 overwrite
reset
import mesh geometry "test1.e" block all use nodeset sideset feature_angle 135.00 linear merge

Additional Resources

View our video tutorials on how to use Trelis.

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