Some Common Modeling Basics

Surface models can be constructed to meet a number of quality levels that depend on the intended purpose of the model and the time allotted for the project. For instance, a model that has to be milled immediately as a 1:4 scaled model will have a different design phase than a model of a digitized master that is intended for a major CAD system (such as CATIA, or Unigraphics).

Surface modeling quality levels

Class A quality (sometimes referred to as Class 1)

Class B quality

Class C quality

Often, quality levels have no fixed definitions as companies often institute their own standards that reflect the demands of their particular industries. Details that are important to surface quality may include the use, or negation of, construction tolerances, highlight standards, trimmed surfaces, radii shape, flange availability, Bezier surfaces, and triangle surfaces.

In general, a surface modeling project can be defined by three questions.

Do the construction tolerances of the continuity between surfaces match the construction tolerances for the required data of the next step (CAD system, milling)?

Do the quality of highlights and curvature combs meet the requirements defined by the designer responsible for the model?

Do the data requirements of an external package match those used to create the model?

When working with SurfaceStudio, you should begin by setting the construction tolerances. The input construction tolerance levels will depend on the type of system employed to execute the design. If you do not know the construction tolerances at the onset of your project, you can follow one simple rule.

Solid modeling systems (Pro/Engineer, SolidWorks) require small position construction tolerances. Ensure your construction tolerance values work with your solid modeling system.

How Different Types of Input Affect the Model

Surfaces can be modeled from several input types. One of the more common methods of surfacing is to base the model on the input derived from a scanned model. Some model scanning techniques can produce point clouds while other scanning techniques produce curves instead of points. Depending on the technique employed during the scanning procedure, the data can be either be sorted or unsorted.

For the purposes of surface modeling it is better to have sorted data. If your scanning technique produced an unsorted point cloud instead of sorted section data similar to the image above, additional work is required to triangulate the points and cut the facets.

Another type of input is derived from a completed surface model that has yet to be modified. In these cases, surface data and hard points can be fitted with a new, updated model.

In other cases, input may consist of a collection of sketches and a package similar to the image below.

Regardless of the type of input data, surface modeling is largely an interpretation of a variety of inputs. For the modeler it is imperative to achieve an understanding of the design and the character of the model. With any surfaced model there are a number of intricate details that lay hidden below the surface, known only to the designer and modeler. Due to the precision of modeling software, the modeler must develop a close working relationship with the designer in order to surface the model. After all, surface modeling is a creative process that finishes a design.

Loading and Organizing Data

To work with saved data, you must first load it into AliasStudio. After you open the data you can organize it into layers, allowing you to manage it more efficiently.

In this lesson, we will show you how to work with SurfaceStudio files, open and organize files.

Opening the Lesson File

Begin by loading sample scan data from a disk. This will demonstrate how SurfaceStudio organizes files into projects. The sample scan data exists in the form of courseware files.

You will find these courseware files on the AliasStudio Documentation CD in the CourseWare/wire directory.

Organizing your files into projects and directories helps you manage your work efficiently. Keeping an organized file system ensures that you do not misplace important data, and makes the archiving process simpler.

File Organization

When you first set up your user account for use with SurfaceStudio, a directory is created in your home directory called user_data. By default, this is where SurfaceStudio stores files that you create.

Inside the user_data directory you will find directories for projects. Project directories allow you to organize all the files associated with a job. Each project directory contains sub-directories for the different types of data, including wire files, cloud data, and pix format images.

The wire directory is used to store wire files. These are the files created when you save a model in SurfaceStudio. These files contain all the information about that model.

The initial set-up creates a project called demo. Until you create a new project, this is the default project.

The user_data directory may also contain a directory called CourseWare. This is where you will find the example files for use in these tutorials. If your user_data directory does not have a CourseWare sub-directory, you must copy it from the AliasStudio Documentation CD.

The sample file you will load contains scan data for a center console from an automotive interior.

Opening a Wire File

To use the Open command to load a model from disk

In the File menu, choose Open.

The file browser appears.

If Type of File Browser is set to AliasStudio in Preferences > General Preferences - (System section), your file browser will look different from the one displayed below.

For step by step instructions on how to load your file using the AliasStudio browser, consult the Introduction to 3D tutorial in Learning AliasStudio.

You are currently in the wire directory of the demo project directory. This is the default location for storing wire files until you set up a new project.

You need to navigate to the CourseWare directory to load the example wire file for this lesson.

Click the arrow to the right of the Go field and select Projects from the lister.

The list of project directories is displayed in the main browser window.

Double-click the Courseware directory in the browser window to display its content.

Click the arrow to the right of the Project field and select Set Current from the lister.

This changes the current project from demo to CourseWare. From now on, the file browser will show the content of the CourseWare directory by default when you open it.

In the browser, double-click the file called Lesson2.wire.

SurfaceStudio asks you if you want to delete everything in your model before loading the file.

Click YES to continue.

SurfaceStudio loads the file.

If you were to answer NO to this request, SurfaceStudio would keep any existing model information and load the new file into a new stage.

Stages are a method of organizing model data in different files. You will not use stages in this tutorial, but you can read more about them in the Basic Tools manual.

Interface Arrangement

To arrange the SurfaceStudio interface

Load the shelf set named SurfaceStudio Shelf.

The SurfaceStudio Shelf is specifically designed for this tutorial. Some tools have been removed from the shelf to allow you to concentrate on those tools required for this tutorial.

Load the Control Panel shelf set named SurfaceStudio Control Panel Shelf.

The Control Panel shelf provides you with a faster avenue to a customized collection of tools. It is a good habit to use a customized Control Panel shelf. As the Control Panel shelf does not offer enough space for all of the icons, use a different method to access the tools. Instead of recognizing icons, you must know the full names of the tools. (For example, the full name of the Fillet tool is Surfaces > Surface fillet).

To access the tools, right mouse click on a given tab to produce a sub-menu pop-up window containing a list of tool names and option boxes (where applicable).

Load the marking menu named SurfaceStudio Marking Menu.

Set the ObjectDisplay > Control -

panel as shown in the image below.

Choose the Preferences > Construction options and click the Catia option. The Construction Options window allows you to set a variety of modeling tolerances. If you will be exporting your data to one of the CAD packages listed in the Construction Presets tab, simply click the name of the CAD package and SurfaceStudio will automatically set the tolerances appropriate to that software.

Open the ObjectDisplay > Draw style option box and set the style of curve and surface CVs as shown in the image below. For beginners, changing the draw style of CVs to these settings will allow for easier recognition.

Save the selected options by choosing Preferences > User options > Save options from the menu.

Restart the computer to make sure your options are saved.

Open SurfaceStudio.

In this tutorial, the modeling process will be conducted solely in the Perspective view. You will be asked to change views in order to facilitate the best possible view of the model. For each instance when you are asked to change views, always use the Viewing Panel located in the Perspective window.

Traditional Surface Modeling

The first step is always the hardest. So, you had better not start with the software. Instead, turn away from your screen and take a little side-trip to a workshop.

Inside the workshop, there sits on a workbench a foam cube that you will transform by hand into a model resembling the one below.

Later in the tutorial, you will recreate and surface the model using SurfaceStudio. Before you begin though, take a moment to imagine what steps you will undertake in building the model. This exercise will provide you with a guide for detailing the construction steps.

You can start by using a pencil to sketch the center line onto the side of the cube body.

Once you have sketched your design onto the foam body, go to the grinding machine in the corner of the workshop and sand your foam block. You will find it quite difficult to sand the entire center line in one step. Instead, try sanding the middle portion first. After that, the front and the rear can be worked independently.

The bottom is easy. You will do it in a similar fashion to the top but using a different tool.

Now, sketch the top view onto your foam block and return to the grinding machine to perform the same procedure as before.

Having fashioned a model from the foam cube, you are left with a theoretical model - a model with no fillets.

Following the taping procedure, sand the foam by hand until you have produced the fillets and rounded corners.

Congratulations, you have produced a foam model using a method that is tried, tested, and true. As we step further into the tutorial, you will use this same classic method to develop your surface model.