Title: Interactive Mesh Sculpting Using a Haptic Device
1Interactive Mesh Sculpting Using a Haptic Device
2Goal
- A method to continuously sculpt or deform a
planar mesh using haptic interaction is
implemented. Moreover, this mesh has an image of
the final model mapped on.
3Approach
- Image mapped on a planar mesh
- Phantom Omni Basic Haptic Device
- NURBS surface is used
- Different tools to improve sculpting
4Force Feedback Foundation
- It allows the user to interact with it by
applying and receiving forces. - Interacts with graphics applications
- Can make objects feel sticky, soft, rough,
viscous
5Previous Work
6Haptic Device
- Avoiding interpenetration between virtual objects
- Allowing the user to paint in virtual
environments - Teleoperation of objects
- Touching textures
7Mesh Sculpting
- Free Form Deformation
- Control points define the vertices of a
parallelepiped - Using control points can be cumbersome
- Subdivision solids
- Each subdivided solid has damping, mass and
stiffness - Virtual clay
8Characteristics of the Project
9Haptic Device
- Movement in 3 dimensions
- Mouse is constrained to 2 dimensions
- Limited range of motion
- Force rendering
10NURBS
- Provide advantages over other surfaces
- Using OpenGL implementation
- Automatic texture mapping
- Knot array affects continuity of the surface
11Particle System
- Defined as a set of particles that evolves over
time - Control points in NURBS are the particles
- Particles have attributes like position, velocity
and force
12Runge-Kutta4
- Method used to solve differencial equations
13Implementation
14HLAPI and OpenGL
- High level haptic rendering
- Provides rendering/collision detection and useful
data structures - hlBeginFrame and hlEndFrame
15Data Structures
- Vertex class
- Has attributes like position and velocity
- ParticleSystem
- Contains list of control points
- NURBS
- Draws the mesh
16Features/Tools
- Sculpting
- Forces are rendered when we touch the surface.
- Sculpting includes both pushing and pulling the
surface. - We are using the stylus button to switch between
push and pull modes.
17Brush
- Induces force on more than one control point at a
time
This is the point of contact
The green points are also affected
183D Paint
- Painting in the 3D model is reflected on the 2D
texture
19Show/Hide Particles
- Showing particles Hiding particles
Closer look at the image
20Rotations
- It allows us to look the image from different
angles
213D Cursor
- It simulates the shape of a pen
22Force Feedback
- This is the default mode, but can be disabled.
- If disabled, no forces are rendered, but the mesh
can still be sculpted. - Results of this comparison are shown in the
Results section.
23Basic Algorithm
- Initialize the application
- Create the mesh and texture map it with the image
- Sculpt the mesh using the haptic device
- Rotate the mesh
- Select a brush or single point sculpting
- Apply forces to the mesh
- The new position for the control point is
calculated and the mesh is drawn again. - Repeat step 3 until sculpting is done.
24Major Issues
- Sense of depth is difficult to implement
- NURBS sampling parameters needs to be adjusted
- Haptic device kicked occasionally while rotating
the surface
25Results
26Comparing the Haptic Device and the Mouse
Mouse Haptic device
No force feedback Points moved one at a time, but can move continuously if implemented User touches the control points Picking control points may be difficult Force feedback exists Points are moved continuously User touches the mesh since the haptic device provides this configuration No need to pick control points
27Mapping Haptic Device to Graphics Simulation
28NURBS in OpenGL
- An efficient way to draw NURBS
- Provide different parameters to control the
surface - The mesh is 12x12 control points
- Hardware acceleration in the graphics card should
be disabled
29Interactive Sculpting
- Initial image Final image
30Lips Deformation
31Sculpting the lower lip
32Side view of the image
33Common error in the sculpting process
34Side view of the final mesh
35Front view of the mesh
36Comparing Force Feedback and No Force Feedback
- Haptic device as a 3D mouse
- Identifying if we are touching the surface
37Example
38Results
- Aesthetic quality of the image and 3D model are
better when using haptic interaction - Some curves in the mesh are not steady
- Same results can be achieved without force
feedback but time will increase.
39Conclusion
40Conclusion
- Haptic interaction provides an easier to use and
faster way to sculpt a mesh. - We implemented a few of the many tools that will
enhance the sculpting process. - Practice is needed to perceive the cursors Z
location.
41Conclusion
- Real time interaction is important
- NURBS provided flexibility and important
properties - Sense of touch can provide new forms of
interaction
42Future Work
43Future Work
- New editing tools
- E.g. a selection tool
- Adding knots on the fly
- NURBS parameters should be adjusted
- NURBS limitations
- How to model hands, bottles?
44Future Work
- Different views of the mesh
- Each view has a different angle
- Integration with image editing software
- Attract users attention
- Image recognition
- Identify boundaries and apply rules to the
control points near the boundary - 3D Paint