Construct Sphere dialog box
There are several ways to construct a sphere using PC-DMIS. The following table lists the various types of constructed spheres, along with their necessary inputs. Some features may require no inputs while others may require five inputs or more. The term "Any" indicates that the construction can take any type of feature as input for construction. PC-DMIS allows the features to be selected in any order.
CONSTRUCT FEATURE TYPE |
SYMBOL IN EDIT WINDOW |
# OF INPUT FEATS |
FEAT #1: |
FEAT #2: |
COMMENTS |
Auto Sphere |
- |
- |
- |
- |
See "Auto Sphere Construction". |
Best Fit Sphere |
BF |
At least 5 inputs are needed. |
- |
- |
Constructs a best fit sphere using the given inputs. See the Note below for recommended inputs. |
Best Fit with Recomp Sphere |
BFRE |
At least 5 inputs are needed. (1 must be a point) |
- |
- |
Constructs a best fit sphere using the given inputs. See the Note below for recommended inputs. |
Cast Sphere |
CAST |
1 |
Any |
- |
Constructs a sphere at the centroid of the input feature. |
Projected Sphere |
PROJ |
1 or 2 |
Any |
Plane |
One input feature will project the sphere to the workplane. |
Reverse Sphere |
REV |
1 |
Sphere |
- |
Constructs a sphere with a reversed vector. |
For Best Fit (BF) or Best Fit Recompensate (BFRE) constructions, while you can use any feature type for your input features, BF and BFRE fit types are typically used with point features or point sets (a scan of points, a feature set with points, or an expression that resolves to an array of points).
If you select inappropriate feature types, PC-DMIS displays "Cannot construct [feature]. Combination of input features not accepted." on the status bar.
To construct a sphere:
Access the Construct Sphere dialog box (Insert | Feature | Constructed | Sphere).
Input the desired features.
Select the method of construction. Available options include:
Auto Sphere
Best Fit or Best Fit Recompensate Sphere
Projected Sphere
Cast Sphere
Reversed direction Sphere
AUTO is the default method of construction. This option automatically determines the best way to construct a sphere using the input feature(s). See "Auto Sphere Construction".
Click the Create button.
The Edit window command
line for a sample Sphere Construction would read:
feature_name=FEAT/SPHERE,TOG1,TOG4
THEO/x_cord,y_cord,z_cord,i_vec,j_vec,k_vec,diam
ACTL/x_cord,y_cord,z_cord,i_vec,j_vec,k_vec,diam
CONSTR/TOG2,TOG3
The actual Edit report displays in all capital letters.
TOG1= POLR or RECT
TOG2 = SPHERE
TOG3 = BF / BFRE / CAST / PROJ / REV
TOG4 = IN / OUT
The first three lines that display in the Edit window are the same for constructed spheres. The fourth line is slightly different, according to the type of feature being constructed. To switch between the different types of spheres, place the cursor on TOG3 and press F7 or F8. (See "Command Mode Keyboard Functions" in the "Using the Edit Window" chapter.)
When two or more features are involved, PC-DMIS automatically determines the necessary order of the input features. This improves the accuracy of the measurement process.
The following topics describe the available options for constructing a sphere.
More:
Constructing a Best Fit or Best Fit Recompensate