 Point cloud to NURBS
Point cloud to NURBS is a stand-alone application. This software can fit a NURBS surface to a point cloud by clicking one button. The feature includes:
1.
Import point cloud file formatted by .xyz and .txt
;
2.
Fit point cloud to a NURBS surface
;
3. Export the surface to .igs file;
4. Controllable precision. The maximum deviation between points and surface can be specified;
5. Controllable surface smoothness. The surface's smoothness can be adjusted by 5 levels;
6. Handle large scale data. Surface control point number can reach 300X300 which allows to fit large scale data.
7. Easy to use. Just click one button to create surface from point cloud.
|
|
Dialog:
After you clicked menu button 'Surface>Point cloud to nurbs' you will see a dialog like the following picture:
Parameters:
-
Pull orietation: pull orientation (dx, dy, dz) is the normal of the fitting plane. The pull orientation determines the quality of surface. Generally, the program will calculate a optimum pull orientation for surface fitting. However, sometimes, it may be bad for some cases.Pull orientation lets user change the orientation (dx, dy, dz) for better surface generation.
-
Control point number: set surface control point in U-direction and V-direction, this control point number will be used as initial number for surface fitting to the mesh. This is optional , program will compute the reasonable surface control point number for you.
-
Surface degree: specify the surface degree in U-direction and V-direction, the default number is U==3 and V==3 the maximum degree is U==8 and V==8.
-
Max deviation: threshold for the maximum deviation between mesh nodes and surface. The items include: no constraint, 0.5, 0.1, 0.0, 0.001, 0.05, 0.3, 1.0, 0.0001;
-
Smoothness: surface smoothness factor, to choose a smoothness level for controlling surface smoothness quality. The items include: highest, high, medium, low, lowest;
-
Apply: click this button to create a surface that fits the mesh. After you have gotten an fitted surface, you can choose a more little 'max deviation' number and continue to click this for updating the surface with higher precision.
- Report: click this button to save the deviation between points and surface into a .txt file as report.
Tutorial to fit a NURBS surface to a point cloud
Step 1 : Open the sample file skidoo.xyz . You will see the point cloud model shown as the following picture.
Step 2: Click menu 'Surface->Point cloud to nurbs', the dialog shows. Some parameters for 'Drape orietation' and 'control point number' have been figured out automatically, you can specify new parameter values which you think more better or click button 'Apply' directly to create a new surface. After you clicked 'Apply' button, wait for a while, a fitted surface will generate.
The RESURF message reports that 'Maximum deviation : 0.162620 ; average deviation: 0.018632'. This means that the maximum deviation between points and surface is 0.16262, the average deviation is 0.018632.
View the surface by rotation:
Step 3: Choose Max deviation as 0.1, continue to click Apply button. The surface was updated.
Resurf message reports as the following picture:
The report tells user the maximum deviation between points and surface is 0.084428 which is under the specified threshold 0.1.
Step 4: Close the dialog. Click menu 'View->mode->Hide mesh' to hide the points, and click menu button 'View->Mode->Show surface CPS' to display surface control point.
Step 5: Click button 'report' to save the deviation report as a .txt file. The report file is formatted as "point id, point (x, y, z), projected point on surface (x, y, z), uv value(u, v), distance".
Step 6: Click menu 'File->save' to save the surface as .igs file.
|
