# PTC Wildfire Surface modeling techniques

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PTC Wildfire Surface modeling techniques
By Mritunjay Kumar

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

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

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 Reference:

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.

Surfaces and shapes Reference:

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:

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. Reference:

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 Reference:

Difference between Nurbs and Bezier
Bezier Surfaces Nurbs Surfaces Bezier Surfaces Nurbs Surfaces Reference: 1. 2

b) Surface modeling process
Difference between surface and solid modeling

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

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 Reference:

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 Reference:

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 Reference:

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 Reference:

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 Reference:

Example of Surface modeling process
Input Sketch Initial Template Final Template Design in progress Triangular mesh near the headlight Surface Model Reference:

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. Reference:

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 Reference:

c) Basic Surface modeling functions
Editing, Merging functions

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

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

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

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

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

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

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

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

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

Create datum curve using different functions Advanced surface modeling functions

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

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

Creating Surfaces by Swept blend Click here Section 1 Select Trajectory Menu for trajectory, Sections and edge continuity Section 2 Insert section 2

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

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

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

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

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

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

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

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

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

Create a new part in Creo Import case_study2.igs
B 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

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

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

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

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

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

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

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

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

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

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

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

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

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

Trace sketch from JPEG or Tiff images
Input Output Reference:

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

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

Thank You

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