3D Digital or Physical Model

CS237 Assignment 6 & 7

 

 

1. Dates

Cinema 4D Help Session

Monday 10/7, 7:00-9:00PM

RISD ISB Lab, Room 303

Out

Tues, 10/8

Due

Sketch, Thu 10/10, final Tues 10/15

 

2. Goals

  1. Combine design knowledge gained in previous assignments in an approximation of the 3D space of the Cave.
  2. Refine color choice and icon design in relation to 3D space.
  3. Gain insight into problems of complex layering of data: issues of simultaneous visibility.
  4. See some vorticity, vortex lines, and vortex cores.
  5. Explore digital or non-digital mediums as prototyping tools for VR visualizations.
  6. Explore 3D perception issues that exist in the “real” world.

 

3. Readings

Keller, P. and Keller, M,.Visual Cues:Practical Data Visualization, Focusing on an Approach pp. 6-13 Images: pp. 115, 127,129,130,147, 154, 156, 167, 165

 

VanDyke, Milton, An Album of Fluid Flow, Chapter 4, Vortices.

 

Benjamin Martinez and Jacaueline Block, Perception Design And Practice

Chapter 6: Space And Flatness

Chapter 7: Three Dimensions in Two

Hagen. Margaret, Varieties of Realism  N7430.5.H33 1986

 Styles emphasizing three-dimensional composition. pp. 225-239

 Station Point Options, pp. 116-156

 

Wenger, Volume Rendering Paper: abstract, sections 9-12.  Look at the flow images.  Vorticity now is not just through the 2D plane, it goes all over the place.

4. Assignment

 

(Assignments 6 & 7 have been merged. You now have the choice of working in digital form, or physical materials. Work on assignments should start immediately; preliminary plans will be reviewed in class on Thursday. If you choose to work in digital form, bring a printout of your initial work on the model or, at the least, a sketch. You should be far enough along to explain how you are thinking about the basic icon set and the spatial arrangement. We will consult together in class on how to solve any technical issues which have arisen, or which might be anticipated. If you are working physically, you should have a detailed sketch of your plan, and samples of any material you are thinking of using. We should be able to suggest other options if necessary. We will have a demo of possible materials and approaches to construction in Thursday’s class.)

 

Build a 3D environment in Cinema 4D, Cave Painting or in physical materials (see below), showing a moment of flow narrative, possibly based on the designs completed for the last assignment, but definitely involving a role for the six flow quantities from the last assignment.  In essence, this is the same problem but more completely in 3D.

 

The special nature of this problem is to convey the complexity of the situation, while allowing all variables to be legible. In this case, we are also looking for a certain sense of life: an evocation of the flow of blood in the artery and the connection of this phenomenon with rivers, plant growth, and other fluid forces in nature. If you are using Cinema 4D, you may employ any of the special characteristics of 3D graphics texturing, transparency etc. in addition to the variables of color and shape that have been part of our previous designs. If you are working in the Cave, experiment with the texture palette, utilizing the meshes and patterns to code data onto your icons and the arterial wall, and to allow visual penetration of layers and surfaces within the model.

If you are using sculptural materials, begin by sketching, and by exploring the qualities of available materials. Some good places to look are: the RISD store, the Metcalf store, hardware stores, your own kitchen, garbage, construction sites etc. Your constructions need not be “pretty” but they should be visually coherent and read intuitively. Because this technique involves found materials, some planning is necessary. A good approach is to work back and forth between idea sketch and material assemblage. In other words, you might start with your image (or any of the other designs) from Assignment 5, and imagine what materials would be suitable to realize your design in three dimensions. Then, hunt for the materials. You may not find exactly what you wanted, but maybe you will encounter some interesting things that you hadn’t considered along the away. Go back to sketching, and see if you can reconceive the project in terms of the new materials.   When you are ready, your sketch works with stuff that you have, you can begin to fabricate the design.

 

All the designs, digital or physical, should make use of the qualities of 3D space. In particular this might mean a concerted movement of the forms through space, a sense of enclosure or layering, a strong role for 3D surfaces of objects, including polygonal geometry or vivid, tactile textures. You may also include a role for specific lighting strategies: using light objects in C4D, flashlights or other fixtures in the physical models. Specific lighting options may not be available in the Cave, but there will be a greater role for physical navigation or penetration of the model.

 

All models should be documented by 2D images. In the case of Cinema4D, manipulate the views of your model in the perspective widow until you get three views that show important aspects of the situation. You can toggle icons or light sources on and off in the objects menu to increase emphasis on the part you want to show in each view. In addition you can change the camera in use by pulling down the camera list in the view window (this is different from creating a Camera Object).  In the Cave, you can save views of you model as JPEGs for print out, arranging the forms in the way you would like them to be seen.

 

If you are documenting your physical model, you can use a camera (digital cameras are available from Fritz or David) or make a drawing. If you draw, make good use of spatial indicators (vanishing point, overlap, color contrast) to project a vivid and useful view of the model. They might involve isometric compression of the space, panoramic extension, or other “distortion” (see Margaret Hagen readings). The drawings do not have to be fully realized in realistic terms, because we have the models to look at in class, but they should be clear enough to show us how you would like us to look at and understand the relationships occurring in your scene.

Use point of view effectively to show the physical relationships between the various elements. Pay special attention to the interplay of graphic factors such as color and shape, with the effects of space. Make adjustments to graphic factors, and to the character of the space (point of view) to increase clarity and legibility.

 

In addition, if you are using Cinema 4D save your model in Cinema 4D format and send to Fritz.  If you are using CavePainting, use the procedure for handing in the color environment from Assignment 3 to hand in your CavePainting. First, you should create a course/cs237/asgn6 directory in your account (mkdir course/cs237/asgn6).  Then, run cavepainting from that directory.  When you are done, hand in your files with the command “cs237-handin 6 login1-login2” where login1 is your login name and login2 is your partner’s. 

 

5. Resources

 

5.0 Possible Materials for Physical Models (Partial List)

 

Clay


Paint

Wire

Screening

Fabric

Rubber

Balloons

Sand

Insulating foam

Saran Wrap

Acetate

Plexiglas

Pipe Cleaners

Ribbon

Epoxy Resin

Acrylic gel

Acrylic modeling paste

Glitter

Twigs

Rope

Plaster

Kneaded Eraser


 

5.1 Saving Screen Shots from CavePainting

While running the program, press “I” on clio’s keyboard.  This will save a mono version of whatever is on the front wall of the Cave to a file called screengrab_0001.tga in your directory.  If you press “I” more than once, the next file will be called screengrab_0002.tga and so on.  Each time you restart the program, it will start over at screengrab_0001.tga, so rename these files when you quit the program so you don’t accidentally overwrite them. 

 

Note that what you see on the front wall of the Cave is not necessarily what you see when you have the glasses on.  This method will save exactly what is on the front wall of the Cave.  To get a reasonable perspective, hold the glasses in your hand and move them roughly to the exact center of the Cave.  This should give you a relatively undistorted view, you may have to move your painting around to position it so that you get a good view on the front wall when the glasses are in this position. 

 

Also, note that the aspect ratio of the saved image will be slightly off because the projectors warp 1024x768 pixels into a square region on the projector screen.  To get your image to look the way it does in the Cave, you’ll have to squash it horizontally.  If you resize it so that it is 768x768 pixels, that should do the trick.  On the linux machines in the Cave, you can use “gimp” to do this.

 

5.2 Importing Cinema4D Models into the Cave

This is very tricky.  This is an extremely optional part of the assignment.  The best export option out of Cinema4D is in VRML format.  However, the VRML viewer for the Cave is written with World Toolkit.  It expects VRML 1.0, but unfortunately, it doesn’t like Cinema4D’s VRML 1.0.  Apparently, VRML 1.0 isn’t a very standard, standard.  I think the way to get this to work is to export VRML 2.0 from Cinema4D.  Import this into another modeling package (3D Studio Vis??).  Then, export it as VRML 1.0 from there.  Then on clio, cd /share/gfx/vrml_viewer and run vrml_view filename.wrl.

 

IMPORTANT:  To avoid scaling headaches, make your Cinema4D model in a scale that works for the Cave.  The center of the Cave is at (0,0,0).  It is 4 units in any direction to get to the walls.  So, if you wanted to make a cube that is the same size as the Cave, it would be 8x8x8 units and centered at the origin.  Up, is the –Y direction.  Right is the +X direction.  Forward into the front screen is the +Z direction. 

 

6. Questions: Digital Model

  1. How does the 3D spatial configuration of your model help or hinder legibility of data relationships as compared with your previous assignments?
  2. Is there a possible role for layering, selection tools, or transparency in clarifying relationships within the data?  Are there disadvantages to any of these approaches?
  3. Are there aspects of the data that present particular problems in visualization?
  4. Is there a model for VR navigation that is suggested by your model?  How can a user/viewer make the best use of your design in exploring the data?

  Questions: Physical Model

  1. Why did you choose the medium(s) that you did?
  2. What types of flow effects or characteristics does your medium lend itself to conveying?
  3. Did you succeed in conveying a particular quality of the flow?  Which one? Were there flow characteristics that were more resistant to description in this way?
  4. How does the reading of the model change from looking at it directly, to looking at it through each of your 3 drawings? Are there advantages to differing spatial modes in conveying the information contained in the model to a viewer?

Does the technique that you examined with your physical medium have a counterpart in the digital world of VR?  Do you think it would be more or less successful at conveying scientific information than your physical model?

 

1.     Checklist: Digital Model

o     Readings

o     Went to RISD Lab or Cave, made a design with Cinema 4D.

o     Saved 3 snapshots of the model from different point-of-views that illustrate the spatial relationships in the data.

o     Saved your Cinema 4D model as a file and sent to Fritz.

-         or -

o     Saved your CavePainting and handed it in.

                                     -     or -

o     Brought your physical model to class.

o     Answered assignment questions.

Checklist: Physical Model

o     Readings

o     Selected and obtained physical media appropriate to illustrating various aspects of fluid flow.

o     Created a model that conveys some character of the fluid dynamics that we have been studying.

o     Created 3 drawings in different modes of spatial projection, working directly from your model and potentially enhancing them digitally.

o     Answered assignment questions.