Access: Click the or icon, or select File / Import / From File or File / Export / To File from the main menu. The Import or export dialog is displayed. Select SAT Files from the Files of Type field.

SAT is an ACIS part save file. ACIS is an object-oriented 3D geometric modeling engine from Spatial Technology Inc. ACIS is designed for use as the geometry foundation within virtually any end user 3D modeling application.

ACIS saves model information to ACIS part save files and also restores the model information from these files. These files have an open format so that applications not based on ACIS can have access to the ACIS model. An example of a non-ACIS based application that needs the geometric model information is a program that translates models from ACIS to another format, or vice versa.

There are two types of ACIS save files; save as text (file extension .sat) and save as binary (file extension .sab). The only difference between these files is that the data is stored as ASCII text in a .sat file and in binary form in a .sab file. The organization of a .sat file and a .sab file is identical. The term SAT file is generally used to refer to both.

Some basic ACIS concepts:

ACIS and C++

ACIS is written in C++ and consists of C++ functions and classes. A developer uses these functions and classes to create an end user 3D modeling application.

ACIS is a solid modeler, but wireframe and surface models may also be represented.

Geometry

Geometry refers to the physical items represented by the model (such as points, curves and surfaces), independent of their spatial - or topological - relationships. The ACIS free-form geometry routines are based on non-uniform rational B-splines (NURBS).

In addition to manifold geometry, ACIS can represent non-manifold geometry. Geometry can be bounded, unbounded or semi-bounded, allowing for complete and incomplete bodies. For example, a solid can have faces missing and existing faces can have missing edges. Solids can also have internal faces that divide the solid into cells.

The ACIS philosophy related to geometric definitions is that the representation be essentially coordinate system independent, numerically stable and easily transformed.

Model Topology

This refers to the spatial relationships between the various objects in a model.

Boundary Representation

ACIS separately represents the geometry (detailed shape) and the topology (connectivity) of objects. This concept is called boundary representation, or B-rep, modeling.

Tolerant Modeling

This allows ACIS-enabled applications to work with low tolerance models (generally imported from other applications) when the geometry cannot be "fixed" to the exact modeling standards of ACIS (e.g. through model healing). Tolerant edge and vertex capabilities allow the software to attach tolerance values to the edges and vertices. So even when edges do not exactly intersect, they are considered "close enough" to be useful.

Entities and Model Objects

An entity is the most basic ACIS object. All entities have a common set of functionality, such as the ability to save and restore themselves to and from a file, copy themselves and debug themselves. All other higher level ACIS model objects are derived from entities.

A model object is any object that can be saved to and restored from a SAT file.

Attributes

Attributes are used to attach data to entities. Every entity may have zero or more attributes. Attributes can carry simple data, pointers to other entities or links to application-specific, variable length data.

Dimensionality

The dimension of an object is the number of parameters needed to specify the position of a particular point of the object. A point that requires one parameter has one dimension; a point that requires two parameters has two dimensions, and so on. In other words:

• Points that lie on a curve are 1D

• Points that lie on a surface are 2D

• Points that lie within a volume are 3D.

Object Space and Parameter Space

Object space is the 3D real number space. A point in object space is denoted by (x,y,z).

Surface parameter space is the 2D real number space. A point in surface space is denoted by (u,v).

Curve parameter space is the ID real number space. A point in curve parameter space is denoted by t.

ACIS has been designed around the concept that everything is modeled in a single number space called the model world, which is a subset of object space. The origin, the point (x,y,z,) = (0,0,0), is the center of the model world.

Continuity

This describes how two items come together. In ACIS, these items may be two curves that meet, two portions of the same curve, etc.. (In the latter case, one is usually describing the smoothness of a curve).

Click the icon, or select File / Import from the main menu. The Import dialog is displayed. Select SAT Files from the Files of Type field.

See SAT Import.

Click the icon, or select File / Export from the main menu. The Export dialog is displayed. Select SAT Files from the Files of Type field.

See SAT Export.