Unknown entities in creating two-layer sphere using 'Sphere' command
Hello, I am creating a two-layer sphere using Sphere command and boolean operation. However, I got four unknown entities (in curve display) which cannot be picked or deleted. As shown in this screenshot: unknown
Since this is a simple geometry, I have no idea how these unknown entities comes. I am using version 4.10.3/4.9.5. Anyone can show me some clue? Appreciated in advance. Qiyue Lu
I copied the corresponding *.geo here:
//+
SetFactory("OpenCASCADE");
//+ This is to set the background mesh size.
//+ Check t10.geo for more information.
lc = 0.04;
Field[1] = Box;
Field[1].VIn = lc / 2;
Field[1].VOut = lc / 1;
Field[1].XMin = -0.1;
Field[1].XMax = 0.1;
Field[1].YMin = -0.1;
Field[1].YMax = 0.1;
Field[1].ZMin = -0.1;
Field[1].ZMax = 0.1;
Background Field = 1;
//+
//+
Sphere(1) = {0, 0, 0, 0.05, -Pi/2, Pi/2, 2*Pi};
//+
Sphere(2) = {0, 0, 0, 0.1, -Pi/2, Pi/2, 2*Pi};
BooleanDifference{ Volume{2}; Delete; }{ Volume{1}; Delete; }
//+
Surface Loop(1) = {1};
//+
Volume(3) = {1};
Delete{ Volume{2}; }
//+
Surface Loop(2) = {2};
//+ Volume(4) = {2, 1};
//+
Physical Surface("innerface", 7) = {1};
//+
Physical Surface("outerface", 8) = {2};
//+
Physical Volume("outersphere", 9) = {4};
//+
Physical Volume("innersphere", 10) = {3};
//+ This command makes all surface meshes pointing to the outward.
ReorientMesh Volume {3, 4};
======================================================================
Actually, this unknown curves come out when using Sphere command to create a ball, even with 1-layer. As shown in code below:
//+
SetFactory("OpenCASCADE");
//+ This is to set the background mesh size.
//+ Check t10.geo for more information.
lc = 0.04;
Field[1] = Box;
Field[1].VIn = lc / 2;
Field[1].VOut = lc / 1;
Field[1].XMin = -0.1;
Field[1].XMax = 0.1;
Field[1].YMin = -0.1;
Field[1].YMax = 0.1;
Field[1].ZMin = -0.1;
Field[1].ZMax = 0.1;
Background Field = 1;
//+
//+
Sphere(1) = {0, 0, 0, 0.1, -Pi/2, Pi/2, 2*Pi};
//+
//+
Surface Loop(1) = {1};
//+
Volume(1) = {1};
//+ This command makes all surface meshes pointing to the outward.
ReorientMesh Volume {1};
========================================================================
Also, these unknown entities come out while using 'circle arc' then extrude to generate a sphere, using following code:
//+
SetFactory("OpenCASCADE");
//+ This is to set the background mesh size.
//+ Check t10.geo for more information.
lc = 0.04;
//+
Point(1) = {0, 0, 0, lc};
Point(2) = {0, 0.05, 0, lc};
Point(3) = {0, -0.05, 0, lc};
//+
Circle(1) = {2, 1, 3};
//+
Extrude {{0, 1, 0}, {0, 0, 0}, 2*Pi} { Curve{1}; }