Importing and Exporting Object File Formats

In addition to its own project files, form•Z can import and export a variety of other formats. These are either object file formats,which transfer descriptions of 2D shapes and 3D objects, or image file formats that contain mostly bit mapped descriptions of scanned, captured, or rendered images. The object format files share a number of identical import and export options and therefore their dialogs share a common format. The common options are discussed first, then the options that are unique to each format.

 

Common object import options

The dialogs invoked when importing object files into form•Z share many common options. They consist of three sections. The top portion contains options for controlling the units. The next section is the common options for modeling (Import As Modeling Objects). The third section at the bottom of the dialog contains the options specific to the format (if any). Where an option does not apply to a certain format, it is dimmed.

 

common_import_opts.tiff
The common import options.

 

 

Setting the units of the imported entities

project_units.tiff
The Project Units Menu.

Most of the format files contain no information about the unit of measurement in which their numerics are written. For example, a 10 in DXF could be inches, feet, centimeters, meters, etc. For these formats it is necessary to tell form•Z what the units are, which is done through the following two pop up menus.

 

Project Units: This pop up menu determines how units will be set in form•Z, when the Add To Project option is not selected in the Import dialog. When on, this menu is dimmed and the units already set in the receiving project are used.

format_units.tiff
The Format Units Menu.

 

Format Units: The item selected from this pop up menu determines how the units in the imported file will be interpreted. From File is available only when the format of the imported file carries unit information and it reads the numbers as in the imported file. As In Current Project causes the units to be interpreted as determined by the selection in the Project Units pop up menu, or by the settings in the import project. All the other items specify the unit of measurement to be used.

 

 

Importing as modeling objects

m_import_grouping.tiff
The Import Grouping Menu.

Import Grouping: The items in this pop up menu set the hierarchy of the imported file. The first item is the default for all formats.

Disabled: When this item is on, no grouping information is constructed.

 

As Groups: For FACT files, when this option is on, their grouping hierarchy is converted into form•Z grouping with each child as a nested group to its parent object.

 

As Layers: For FACT files, when this option is on, the top level of each group in the file is represented as a form•Z layer, and all the children of the group are placed on the layer.

Import Method: This group of options controls the method used for converting imported objects to form•Z objects.

 

Parametric: To the extent possible, all parametric object data, NURBS data, smooth (ACIS) data will be preserved.

 

Facetted: All objects will be imported as plain facetted objects.

 

Display Resolution: This option sets the display resolution of imported smooth objects.

 

Skip Point Objects: Point objects are sometimes difficult to work around. Selecting this option will prevent point objects from being imported.

 

Skip Text Objects: Some files contain text used for annotation. It may not be desirable to import this text. Selecting this option prevents text objects from being imported.

 

 

Component Import Options
The Component (Block) Import Options

Components: Files can contain components or blocks. These are separate files that may be referenced by the file that is being imported. They help save memory whenever a common element is placed multiple times in a file.

Explode Components: when importing files that contain components or blocks it is often useful to maintain these in some way. You can choose to discard this information, and there are several options available for handling these entites.

 

Import Referenced Component Definitions: this option will import components or blocks that are actually placed in the project, and ignore any that are a part of a library that have not been placed.

 

Import Non Referenced Component Definitions: this option will import all components or blocks that are associated with the project, including those in attached libraries.

 

Ghost Objects Derived From Component Definitions: this option will import the components or blocks that are associated with the project and ghost them.

 

Group Objects Derived From Components: this option will import the components or blocks that are associated with the project and group them.

 

Embed Components in File: this option will import all components or blocks that are associated with the project and place them into the Embedded Component Library.

Transformation: this button invokes an Import/Export Transformation Dialog, and contains simple controls for flipping coordinate system axes, inverting faces, ensuring Normals Point Outward, or simply scaling, rotating, or moving objects in import. This is used for esablishing import pipelines for 3rd party apps that may treat aome of these characteristics of the file differently.

 

Text Options currently has one option: Replace Unavailable Fonts With: This is a menu that lists the fonts available on the system form•Z is running on. If a file to be imported references a font that is not available, the font selected from this menu will be used as a substitute.

 

Constructing solids from closed polylines

Composition: Three dimensional entities imported from other applications are typically collections of polylines which, when taken together, enclose an entity equivalent of a solid. There is typically no information about which polylines belong together. The options in this group tell form•Z how to import these entities into its modeling environment in a meaningful manner.

Construct 3D Solids: When this option is on, groups of surfaces whose edges touch are compiled and solid objects are constructed from them, provided these sets of surfaces are complete and satisfy the closure requirement. That is, for form•Z to be fully successful in this task, the imported data should contain all the surfaces that are needed to completely enclose a solid object. form•Z does not attempt to create faces that may be missing. It will create as many solid objects as possible. Surfaces that fail to incorporate in the representation of a solid are imported as surface objects.

Combine Surfaces With Different Materials: When this option is selected, surfaces with differing materials will be combined to make solids. If this option is not selected, only surfaces with the same material will be combined.

 

Combine Surfaces With Different Layers: With this option selected, surfaces on differing layers will be combined to make solids. If this option is not selected, only surfaces on the same layer will be combined.

Join Adjacent Coplanar Faces: When this option is selected, the system will automatically join all adjacent (sharing an edge) and coplanar faces of the same object into single faces. This option is independent of the Construct 3D Solids option.

 

Make Reference Object: When this option is selected, all imported objects will be joined into one reference object. This is useful when the imported file contains many small separate line objects. form•Z's objects are fairly memory intensive, so combining all the imported geometry into one object saves system memory. All parts of a reference object are snapable so the object can be used for tracing to reconstruct the geometry in a more useful form.

 

When Per Layer is also on, a separate reference object will be created for each layer.

Importing materials and textures

When importing entities through a file format that handles colors, these colors also need to be imported or approximated as closely as possible. Most use an RGB representation for colors, which is consistent with what form•Z uses.

 

Import Textures: If this option is selected, textures will be imported.

 

Common object export options

common_export_opts.tiff
The common modeling export options.

As with importing, the dialogs invoked when exporting modeling object files share many common options, which are displayed at the upper portions of the dialogs. The lower sections contain format specific options. Where one of the common options does not apply to a format, it is dimmed in the respective dialog.

 

 

Notation and platform types

m_platform.tiff
The Platform Menu.

When exporting to formats that support both ASCII and binary notations (SAT and STL) options to select one or the other are available.

 

File Type: This pop up menu contains two items: ASCII and Binary. Either one can be selected. All the export file formats that can be saved as ASCII text, except SAT, support the Platform pop up menu. Most file formats that are exclusively ASCII always have the Platform menu available. For file formats that can be either ASCII or binary the Platform menu is available when ASCII is selected and dimmed when Binary is selected from the File Type menu. The default selection of Platform is initially set according to the platform form•Z is currently running.

 

Export units

m_grouping_method.tiff
Units Menu.

The following option applies when a format does not contain its own unit specification method.

 

Units: This pop up menu sets the linear units of the exported data. When the Project Units item is selected, the data is exported in the units set in the Working Units tab of the Project Settings dialog. When one of the other items is selected, the respective unit is used to export the data.

 

Note again that the options in this menu only apply to formats that do not have their own unit specification options. The ones that do, such as Lightwave, use their own specifications. For these formats this pop up menu is dimmed and unavailable.

 

Grouping method

m_grouping_method.tiff
Grouping Method pull down menu.

When exporting a form•Z project, the objects it contains may be structured as a single group or as many groups. These groups can be structured to contain one object each, all the objects of the same color, all the objects on the same layer, or all the objects that belong to the same form•Z group. When exporting to DWG, DXF, FACT, and OBJ, which provide grouping structures, these groups can be exported in a single file, or one file can be constructed per group. When more than one file is exported from a single form•Z project, they are placed in a folder.

 

Grouping Method: This pull down menu contains five grouping methods.

Single Group: With this method (default), all objects become a single group and one file is exported.

 

By Object: With this option, each object becomes a separate group. When Separate Files is also on, then each object is placed into a separate file.

 

By Material: When this method is selected, all form•Z objects or faces of the same material form a separate group. For file formats that do not carry color or material, this method allows you to reassign uniform colors or materials to groups of objects after they have been imported into other programs.

 

By Layer: When this grouping method is selected, all form•Z objects that are on the same layer are grouped together, which allows you to preserve the layers set up in the form•Z file.

 

By Group: Selection of this method preserves the form•Z groups and transforms them into the grouping structure of the destination program, if one exists, or exports them as separate files.

Separate Files: When this option is selected, a separate file is constructed for each of the groups defined by the selection from the Grouping Method menu. These separate files are all saved into a newly created folder, which takes its name from the name entered into the name field of the Save dialog. The names of the individual files are constructed from the grouping method and an extension that specifies the type of file. For the first part of the name, if the grouping method is By Object, the object name is used; if By Material, the material name; if By Layer, the layer name; and if By Group, the group name is used. This option is dimmed and inactive when Single Group is selected.

 

Export method

This group of options specifies how form•Z objects will be exported.

 

Parametric: When this option is on, parametric objects and smooth (ACIS) objects will be exported to the extent supported by the file format.

 

Facetted: When this option is selected, all objects will be exported as plain facetted objects.

Triangulate All Facetted: When this option is selected, all objects will be triangulated.

Visible Layers Only: All the export formats allow you to export only parts of a project by organizing it into layers that may or may not be visible. When this option is on, only the objects on visible layers are exported.

 

Picked Objects Only: When this option is on, only the objects that appear selected on the screen will be exported.

 

Exporting materials and textures

In form•Z, different colors may be assigned at the object and face levels, as well as rendering parameters relating to the smooth shading of surfaces. Material parameters and texture maps may also be assigned. The ability to export these parameters is available for many of the export formats using the following options.

 

Attributes: This section contains options that specify how colors, normals, shading, and textures are exported, as follows:

Fix Smooth Shading: Rendering applications apply smooth shading across surfaces that share common edges. When smooth shading between two neighboring surfaces is not desired, these surfaces should be disconnected and represented as independent surfaces. To achieve these effects, a form•Z model can be decomposed into parts using modeling tools available in the program. This option can also be used to determine which faces will be exported as continuous surfaces (and are thus smoothly shaded), and which faces will be exported as independent surfaces. The distinction is made on the basis of the angle at the common edge of two surfaces, which is entered in the Angle field, typically found next to this option in the export dialogs. When this option is selected, only the faces whose angle is less than that shown are exported as continuous surfaces and are smooth shaded by the rendering application. Neighboring faces with larger angles are exported as discontinuous surfaces.

 

High Quality Smoothing: When this option is selected, the exported file will contain more accurate smoothing normals. This is intended for situations where the exported data is to be used for rendering and the quality of the smoothing normals is more important than the cleaning of small features in the object's mesh. This option should NOT be used for 3D printing applications or any situation where a water-tight model is important.

 

Hi_Quality_Smoothing.png
High Quality Smoothing: Off (left), High Quality Smoothing: On (right).  Rendered in Electric Image.

 

Textures: If this option is selected, textures will be exported.

Image File Format: This menu lists the texture image files supported by the file format. Use this menu to select the texture image format.

 

Options...: This button brings up the image export options dialog for the selected texture image format. For a description of this dialog, see the Common Image Export Options section later in this manual.

Tips and warnings

The following are some recommendations that will produce the best results, when exporting/importing texture map parameters:

 

When importing a file without importing its textures, only the file you select is imported. When you import with the Import Texture Maps option on, in addition to the main file, a number of other support files, mostly image maps, also need to be imported. Texture map importing relies heavily on the validity of these support resources. Make sure that all the support files (image maps and material files) required by the main file are present; that they are compatible with the main file; that they are of an image type recognized by form•Z, if they are images; and that they have correct file names. If one or more of the above mentioned conditions are not satisfied, error messages are issued and importing may terminate. Needless to say that when you have an incomplete set of support files, the main file can still be imported by turning off the Import Texture Maps option.

 

When exporting spherical or cylindrical texture maps applied to relative large surfaces, which are converted to UV coordinates, the exported models may not render accurately in other applications. You may improve the rendering quality these applications can produce from such maps by increasing the resolution of the form•Z models, using one of the Mesh tools. When special cases are encountered as you import/export files with texture maps, you are warned at the end of the operation. These cases include file name changes due to file format syntax restrictions, image map conversions, failure to locate image maps, or exporting files with unsupported image formats.