| Workshop 2b | |
|---|---|
| Course | Arch 200c |
| Date | 2014/10/02 |
| Learning Objectives | A survey of modeling aids in Rhino, understood to include any method for moving beyond the compositional placement of individual design elements and toward the definition of more abstract generative structures. These include methodological practices, such as the "CAD Factory" approach to modeling, as well as inbuit commands in software, such as CAD blocks, arrays, and selection mechanisms. |
| Agenda |
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| Uses Tool(s) | |
Rhino II: Modeling Aids and Strategies
The "CAD Factory" Approach
The "CAD Factory" approach refers to a method of constructing a 3D model, while at the same time building an explicit history of the decisions and steps of that reflect the way it has been constructed.
It is a method of creating multiple instances of your 3D model by copying and dragging your model next to the previous instance, in order to continue modeling without losing the information of the previous step, while at the same time being able to compare the new instance to the old one.
Finally, when your model reaches a level of satisfaction, you will notice that your drawing space in Rhino has become a series of instances of your model that reflect both your decisions and history of the steps that you followed in order to reach a level of completion. Then, you usually keep only the final instance of the model, delete the previous ones and then Save as to a new files that contains only the final instance.
In order to define this approach more clearly we will compare it with an analogous approach Adobe Photoshop. Photoshop allows you to access a history tab called History . This can be found in the menu Window --> History .
This tab allows us to keep track of the history of the design steps by creating a list that hold every instance of the drawing in Photoshop. If you "click" on a certain intense of that list (other than the last one) you will notice that your drawing will be modified to that instance of history. Photoshop grays out all the rows that are below the one you clicked, but you can still access them by clicking to another instance of the history and photoshop will retrieve your drawing. In this way you can navigate through the history tab and adjust your decision to your current intentions. Even if you use the same tool more than once, Photoshop stores it as a discrete step in the history tab.
Notice that photoshop allows for 20 steps in the history tab. If you wish to store more than 20 instances of your drawing you can save "snapshots" of them in the history tab (merge into one instance that keeps the layer structure of your drawing) and refresh the number of the 20 steps.
Since Rhino does not allow the same kind of inbuilt, history manipulation, the "CAD Factory" approach" is a way to manually store multiple history instances of your model in the design space. You end up with a "decision tree" of your model. The critical deference in this is that through this procedure the location (x,y) coordinates of your model changes. The "CAD Factory approach" can be used in cases of abstract drawing, where you are not constrained in a specific set of coordinates. In cases where your model needs to be set in certain coordinates you have to come up with another method of keeping track of your history, usually through multiple saving as or layer manipulation.
Results-Oriented Modeling
Level of Detail
Depending on the scale you'll be exporting your images or drawings to, your level of detail will have to accomodate it. For example, extremely detailed window mullions won't be able to be seen from an urban context view of a model, but you will be able to see them in a 2d detail drawing at 1/4" scale. It's important to remember that the more geometry that is in a CAD file the larger the file becomes and the more demanding it becomes of your computer's resources.
Utilize layers to create the same object at multiple levels of detail. Begin with the least detailed level (a massing model) and add detail with each successive layer. When you're ready to export or render, you'll have much better results.
Anticipating Use (2d Drawings, Renderings, Lasercut, 3d Print)
Always keep in mind that sometimes the model that we choose to produce drawings from may be different from the model that we choose to produce renderings from or the model we use for fabrication. This is because each procedure has its own requirements and restrains. Be diligent about anticipating how you'll be creating the final output of each model, and consider separating out your completed design into multiple files based upon use and detail.
2d Drawings
As discussed in our earlier workshops on orthographic drawings, the scale of the design's representation will directly influence the amount of detail that is included in the drawing. Take into consideration what would be seen in plan, section, and elevation based on the reproduction size, and test print as you develop your drawings to ensure their legibility. Sometimes 3d models come out too detailed for proper orthographic drawings, and must be cleaned up extensively in Illustrator or Rhino. Save yourself the trouble and the time and clean up your model before exporting or using the Make2d command - and remember that you can always turn off layers or use Save As to create a new model you can manipulate without interfering with the rest of your completed model.
Renderings
Your tendency may be to feel that you must include as much detail as possible in your 3d model in order for it to appear correct in renderings, but it is most of the time unnecessary. Extra geometry in your file, that must go through raytracing to determine how light reflects off of it and into the camera, will add to your render time and hinder you from producing everything you need for your project. Remember that renderings can be post-processed in Photoshop to have complex materials that would take many hours to render.
In general, consider only the geometry that will be seen in each of your rendered images as what is necessary; door hinges, fasteners, detailed window mullions - none of it will be seen in most architectural scale renderings and will only take precious extra time to render. Furthermore, keep the complexity of materials in your renderings to a minimum and consider how you can use Photoshop to achieve similar results in less time.
Lasercut, 3d Printed, and CNC-Milled Models
Modeling is heavily dependent upon the material that is being used to create the model, the method of construction, the restrictions of the mode of fabrication, and of course the scale of reproduction. The typical minimum size that a laser cutter can cleanly cut out of most materials is 1/8" - any lower than that and you come increasingly close to having a thin, mostly incinerated and unusable piece for your model. 3d printers however have restrictions set by the printing material, whether it's starch, plastic, or another medium. Finally, CNC mills are mostly restricted by the drill bits available and the stock used to be milled. The best practice here is to check on the scale that your producing at, and check with the machine operator if you have any questions about the capabilities of the machine.
Tools in Rhino that will help
C Planes
The C Plane or Construction Plane is defined as a local coordinate system (x,y,z) for the viewport that your are currently operating on. The CPlane can be set to any orientation and helps you manipulate your model in a quick and accurate way. The following link covers all the necessary attributes that aid your modeling with CPlanes.
Saved Views
You can save your current Viewport by using the command NamedViews . This command helps you save, restore and edit your named views. To sea your views, Right click on each viewport title and you'll see a drop down menu; go to Set View and click on Named Views . Here you'll be able to save your current view in the currently selected viewport and give it a name.
Blocks
Blocks are a group of 2D or 3D objects that are saved and can be imported from an external drawing. The kinds of objects that are usually defined as blocks are standard objects, like doors furniture etc. , which can be used as a kind of "library" for multiple drawings. This method becomes handy when you use these objects in different drawings simply by importing them, without having to redraw them each time. Moreover, you can update the blocks of your drawing by editing the geometry that defines the block. This will automatically update all the blocks of the drawing. The following link goes through the overall procedure of how to create and modify a block in Rhino.
Selection Mechanisms
Rhino allows for multiple ways to select objects. Besides the common tools of window and cross selection (window: from left to right, cross: from right to left), there are several ways to filter the selection method, based on categorizations.
Some of the most common categorizations are:
- selection according to the type of geometry (points, lines, curves, surfaces, polysurfaces meshes etc.)
- selection based on the type of the object
- selection based on color of the object
- selection based on the layer of the object
- selection by block
- selection by group
- selection by visibility
- selection by SubObject: a command that is only available in Rhino 5 and allows you to select parts of objects such as surfaces, edges, control points, mesh vertices and faces, objects within a group.
To select sub objects press Ctrl + Shift + Right mouse click and apply window or cross selection To deselect press Ctrl + Left mouse click and apply window or cross selection.
Rhino offers a specified command for each of the above categories. You can use the Help section to see all the kinds of selection commands.
What is important here, is that these commands help you manipulate your model more efficiently and faster. Especially when you have a large number of objects on the scene, these commands allow you to select all the objects automatically, based on the property of the filtering.
Related
- Analogous 2013 Session
- The above content roughly corresponds with this class session from last year.