1. PTC Wildfire Surface modeling techniques
By Mritunjay Kumar

2. Course Content Surface modeling overview Surface modeling process
Basic Surface modeling functions
Case study for Basic functions
Advance Surface modeling Functions
Case study for Advanced functions
Create complex surfaces using proper techniques
Case study for surfacing techniques
Repair imported data by IDD function
Case study for IDD functions
Create Surfaces from Scan data
Case study for scan modeling

3. a) Surface modeling overview
Introduction of surfaces and shapes
Nurbs/Bezier Curves and surfaces

4. Introduction of Surfaces
A surface is a two-dimensional, topological manifold. The most familiar examples are those that arise as the boundaries of solid objects in ordinary three-dimensional Euclidean space R3 — for example, Shapes like Sphere, cylinder and flat surfaces are coming together and form free form surface and those are complex quilts in pro/e language
Surface modelling is different technique to create complex shapes which are not possible by solid modelling tools and sometimes we need to create different uneven shapes to fulfil design requirement and there are different kind of shapes are creating one surface quilt
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5. Introduction of Shapes
Simple shapes can be described by basic geometry objects such as a
Set of two or more points
Line, Curve, Plane, Square, Circle, Cube or Sphere.
Concave or Convex type
Most shapes occurring in the physical world are complex and those are two types Non rigid and Rigid.
Reference: 1. 2.

6. Surfaces and shapes
Reference:

7. Surfaces and Shapes
Example of a rim part global modification. The constraint is on the upper boundary
(G0+G1+G2 fixed). The handle is the lower curve (translated).
Rim part before deformation
Rim part after deformation
Tangent and Curvature continuity between two surfaces are playing important role into surface modeling to achieve require shapes
Reference:

8. Nurbs and Bezier
Nurbs: Non-uniform rational basis spline (NURBS) is a mathematical model commonly used in computer graphics for generating and representing curves and surfaces. It offers great flexibility and precision for handling both analytic (surfaces defined by common mathematical formulae) and modeled shapes
Bezier: Bezier surfaces are a species of mathematical spline used in computer graphics, computer-aided design, and finite element modeling. Bezier surface is defined by a set of control points. Similar to interpolation in many respects, a key difference is that the surface does not, in general, pass through the central control points; rather, it is "stretched" toward them as though each were an attractive force.
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9. Difference between Nurbs and Bezier
Nurbs Surface
Complex area possible by single surface
Less flexibility as patches are connected
Control points are always connected directly to the curve/surface
NURBS evolve into two parametric directions, called s and t or u and v.
Bezier Surface
Complex area possible by patch subsets
More flexibility for individual patches
Control points are not connected to each other
Bezier evolve into only one parametric direction, usually called S or u
Nurbs surface divided into subsets called Bezier
Single Nurbs surface
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10. Difference between Nurbs and Bezier
Bezier Surfaces
Nurbs Surfaces
Bezier Surfaces
Nurbs Surfaces
Reference: 1. 2

11. b) Surface modeling process
Difference between surface and solid modeling

12. Surface modeling process steps
Create datum features in model which represents main skeleton
Plan feature sequences based on shell or closed type part
Create surface patches using curves and sketch entity
Complex shapes can be achieved by Boundary blend and other functions
Define draft to all surfaces w.r.t die direction
Merge all surfaces to each other and create single quilt
Create rounds on edges at last before thickening part
Add holes and cutout features on thicken or solid part
Assign material and other parameters to part

13. Surface modeling process for 2D sketch
User's 2D concept sketch
3D template
model
After aligning the template with the sketch user draws directly on the sketch.
Final shape obtained after modifying the template and adding new feature edges
Final solid model after surface creation and Modification
Overview of Surface modeling process
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14. Template alignment Back User draws an approximate
bounding box on the sketch and marks its eight corners
Default conjuration of the template is an orthographic side view
the corners of the template bounding box would exactly match the red dots marked by the user
Back
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15. Modification of a 2D curve
New shape of the target curve. The original curve is shown dashed for reference.
Original curve and the
modifier strokes.
Back
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16. Initial Surface Model Back
Preliminary triangulation using a vertex created at
the centroid
Initial boundary loop consisting of
four curves
Edge swapping
Final result after face splitting
and mesh smoothing using V-spring method
Back
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17. Surface modification Back Initial surface model
Concavity applied to surface keeping
the boundary vertices fixed
Modification of seat base by manipulating control point structure
Back
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18. Example of Surface modeling process
Input Sketch
Initial Template
Final Template
Design in progress
Triangular mesh near the headlight
Surface Model
Reference:

19. Surface and solid modeling
Surfaces and solids are the underlying math that defines the geometry of the forms you create. There are three ways to define 3D geometry: solids, surfaces and wireframes. Wireframes don’t play much of a role in CAD, but primarily in digital content creation (DCC) and gaming. The easiest way to understand the difference between surface and solids modeling is to think of a water balloon; the water in the balloon would be solids modeling, while the latex skin would be surface modeling.
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20. Difference between surface and solid modeling
Surface Modeling
Solid modeling is defining an object with geometric mass
Surface modeling is defining an object’s exterior with an infinitesimally thin skin
Solids modeling programs usually create models by creating a base solid and adding or subtracting from it with subsequent features
Skin is created by lofts, sweeps, and NURBS curves - i.e. sculptured surfaces with lots of curvature
Features such as extrudes, extrude cuts, revolves, radii, chamfers, etc. Examples of solids modeling programs are Solidworks, CATIA, and ProEngineer
The surfaces are either defined by poles or guide curves. A surface is considered a solid only when it is completely enclosed. It is used to make technical surfaces (e.g. air plane wing) or aesthetic surfaces (e.g. car’s hood).
It was originally developed for machine design, and is used heavily for engineering with large part assemblies, digital testing and rapid prototyping
It was developed for the aerospace and automotive industries in the late 70s. Rhinoceros 3D and Alias Studio Tools are examples of a surface modeling programs
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21. c) Basic Surface modeling functions
Editing, Merging functions

22. Basic surface modeling functions
Creating Extrude surfaces
Change mode from solid to surface
Select sketching Plane
Create sketch and assign depth

23. Basic surface modeling functions
Creating Revolve surfaces
Change mode from solid to surface
Select sketching Plane
Create sketch then define rotation axis and angle

24. Basic surface modeling functions
Creating Fill surfaces
Select existing sketch or create a new
Select sketching Plane
Create a sketch

25. Basic surface modeling functions
Creating Sweep surfaces
Select mode from solid to surface
Pause for sketch menu to create trajectory
Create trajectory and define start point
Create a sketch
Select on icon to start sketch

26. Basic surface modeling functions
Creating Blend surfaces
Select mode (Sketch or Selected)
Section 1
Insert section 1
You can define normal condition with Plane at both side sections
Section 2
Insert section 2 and define offset value

27. Surface editing and Merging functions
Trimming surface by extrude option
Surface trim by thicken
Surface mode
Surface trim by extrude

28. Surface editing and Merging functions
Extending surfaces
Click here to extend surface
Select surface edges
Different options to extend surface

29. Surface editing and Merging functions
Trimming and merging operations
Different options will be performed during training
Open trimming_merging.prt
Input
Output

30. d) Case study for basic functions
Case study will perform during training session using basic surface modeling functions.

31. e) Advanced surface modeling functions
Create datum curve using different functions
Advanced surface modeling functions

32. Datum curve functions Creating curve through points
Spline curve passing through all points
Select datum point feature from model tree
Different techniques will perform during training session

33. Datum curve functions Creating blend curve
Select end point 1
Select end point 2
Tangent condition at end point 1
Differed techniques will perform during training session
Tangent condition at end point 2

34. Advanced Surface Modeling Functions
Creating Surfaces by Swept blend
Click here
Section 1
Select Trajectory
Menu for trajectory, Sections and edge continuity
Section 2
Insert section 2

35. Advanced Surface Modeling Functions
Creating Surfaces by Boundary blend
1st direction
2nd direction
Define tangent continuity
Select Curve 1
Select Curve 2
Define tangent continuity
Selection for 1st direction
Input
Output

36. Advanced surface modeling functions
Creating Sweep surfaces with multiple trajectories
Click here to select multiple trajectory
Origin
Chain 1
Chain 2
Chain 3
Trajectory selection menu
Enter sketch mode
Input
Output

37. Advanced Surface Modeling Functions
Creating Surfaces by N sided blend
Open N-sided_patch.prt
Select all edges together then click on Done
Click on N-sided surf
Output
Input

38. Advanced Surface Modeling Functions
Creating surface by Graph feature
Open part graph_sweep.prt
Create graph feature
Sketch a geometry
Create sweep surface
Define relation in sketcher mode
Select trajectory
Sketch should contain coordinate system

39. Advanced Surface Modeling Functions
Using trajpar with sweep surface features
Open trajpar.prt
Create sketch
Select trajectory to create sweep feature
Magnitude is 10
120 is mean diameter
Trajpar varies from 0 to 1
35 Cycles
SD3 denotes circle diameter
Enter relations
Sketch circle

40. Exercise will performed during training session
f) Case study for advanced functions
Input
Output
Exercise will performed during training session
Reference:

41. g) Create complex surfaces using proper techniques
Working with 3D curves and Surfaces
Geometry Analysis functions

42. Datum curve functions Creating offset curve
Select edge
Offset by variable
Variable dimension value 160
Variable dimension value 380
Differed techniques will perform during training session

43. Working with 3D curves and surfaces
Input
Output
Refer next slide to proceed further

44. Create a new part in Creo Import case_study2.igsB
Create a new part in Creo
Import case_study2.igs
Name assign to surfaces for identification
Repeat same process for surface B
Click on Surfaces > Surface free form to create untrimmed surface
Click on Surface A to create untrimmed surface
Next level activities to be perform during training session

45. Working with Draft and B-side design
Input
Output
Activity will perform during training session

46. Geometry analysis functions
Curvature using sections
Curvature section tool can analyze curvature along sections for selected surfaces. reference, System creates a series of porcupine

47. Geometry analysis functions
Offset Surface or Curve
Offset surface analysis can create a surface mesh at an adjustable offset value from the selected surfaces. This is useful to check overlapping of the surface mesh reveals locations which could cause problems when thickening part

48. Geometry analysis functions
Analyze draft angle
Select surfaces or solid geometry
Select pulling direction
Enter draft angle
If draft value is 3 then flanges may have different color

49. Create 3D surfaces and thicken part
h) Case study for surfacing techniques
Create 3D surfaces and thicken part
Input
Output

50. Surface modeling by master model technique
The Master Model technique is a style of surface modeling with top-down-design methodology. Master modeling technique is used to design products that use multiple interlocking body components to form an enclosure with an overall styled shape.
Input
Output

51. i) Repair imported data by IDD function
Redefining & Deleting Imported Geometry
Heal & Collapse Geometry

52. Import data doctor tool overview
Import data doctor(IDD) tool can repair imported geometry. Gaps between surfaces and tangent continuity defined by IDD. Following are the common errors which can be found in imported geometry
Bad surfaces (concave domain or boundaries with parallel)
Bad two-sided edges
Bad wireframe curves
Poorly tessellated edges
Short one-sided edges (warning)
Bad vertices (warning)
Unsatisfied wireframe
Unsatisfied tangency
Gaps not added to wireframe
Non tangent edges
Small surfaces

53. Imported geometry process flow
Import iges or other type surface data in Creo
If any open gaps and errors found then repair it by Import data doctor
Study surface model and plan next activity
Create free form surface using Surface free form option
Create sketch, points or curves to start surface modeling operations
Create surfaces by extrude, sweep or boundary blend option
Trim/cut surfaces by extrude, trim or extend option
Merge overlapping surfaces by Merge Intersect option
Solidify or thicken surface to get final model

54. Surfaces is not tangent continuous
j) Case study for IDD functions
Input
Surfaces is not tangent continuous
Open area need to fill
Open area need to fill
Output

55. Create a new part in Creo
Click to enter for IDD editing environment
Click to enter for IDD editing environment
Training session activity

56. k) Create surfaces from scan data
Create 3D surfaces from Scan data
• Trace sketch from JPEG or Tiff

57. Create 3D model from scan data
Import scan data file in Creo or Wildfire
Check part location w.r.t top level assembly
If not placed properly then move it to correct location
Verify scan quality and study part shape and boundary
Create datum planes and X-sec passing through scan data
Create datum curve by X-sec option
Create sketch and 3D curves using X-sec curve and Scan data
Create surfaces from curves and build features
Check deviation between scan and surface data

58. Trace sketch from JPEG or Tiff images
Input
Output
Reference:

59. Create a new part in Creo
Click to add images
Use different functions from Images menu to adjust its position
Select Image Deodrant1.jpg and
Repeat same activity to import Deodrant2.jpg
Select plane to place Image
Activity will perform during training session

60. l) Perform scan modeling exercise
Create a new part in Creo
Import faceted data casestudy_l.stl
Activity performed during training session

61. Thank You