Initial Graphics Exchange Specifications (.iges) import/export

Initial Graphics Exchange Specification (.iges) defines a vendor-neutral data format that allows the digital exchange of information.

Import

To open, import, insert, and attach a file as a worksession

  1. From the File menu, click Open, Insert, Import, or Worksession > Attach.

  2. In the dialog box, select a supported file type.
  3. Click Open and configure the settings.
    When you open a non-3dm file and save the model, its filename will be the default 3dm filename.

Import notes

Export

To save as or export a Rhino model

  1. On the File menu, click Export Selected or Save As.
  2. In the dialog box, the Files of type list displays the currently supported file types for export.
  3. In the Files of type box, select the supported file type.
  4. In the File name box, select or type a file name.
  5. Specify what is to be saved.
  6. Options

    Save small

    Though clearing the render meshes makes the file smaller, it will shade and render more slowly the next time you open the file.

    Save geometry only

    Saves geometry objects only. No layers, materials, properties, notes, or units settings are saved. This is similar to exporting the objects. A new file is made, but it does not become your active Rhino model.

    Save textures

    Embeds external textures used by materials, environments and decals into the model.

    Save plugin data Saves data attached to objects or the document by plug-in applications.
  7. If the export can be configured, click the Options button to specify export settings.
  8. If the file type creates only mesh objects, in the Polygon Mesh Objects dialog box, specify the mesh settings.

IGES Export Options

IGES type
Always use these settings. Do not show this dialog again.

Saves the current settings and turns off the dialog display.

To turn the message back on

See also: ResetMessageBoxes command.

IGES Export Detailed Options

IGES type

Specifies a pre-defined IGES type that attempts to match requirements in target software.

Edit Types

Click to customize existing IGES types or to create new IGES export types.

Author / Organization / Sender's product ID / Receiver's product ID

These are text fields in the IGES file that can be used for identification purposes.

IGES tolerance

In general, the IGES tolerance should match the absolute tolerance setting in Rhino, taking account the possible unit conversion.

The IGES tolerance does not affect the accuracy of the geometry.

IGES units

The units used for the IGES export.

Include Rhino notes in the IGES file

Check to save notes in IGES start section. Otherwise, the IGES start section is a blank line.

Use render color as IGES entity color

Check to use the render color of objects as the IGES entity color. Otherwise, Rhino uses the layer color of the object as the IGES entity color.

Always use these settings. Do not show this dialog again.

Saves the current settings and turns off the dialog display.

To turn the message back on

See also: ResetMessageBoxes command.

Export note

IGES Type Details

General

Name

Type a name for the IGES type.

See: Naming conventions in Rhino

IGES version

Choose between IGES version 5.2 and 5.3.

The difference is 5.2 stores years if you use two digits and 5.3 if you use four digits.

Text file type

Choose among MS-DOS, Unix, and MacOS style line endings.

Windows (CRLF)
Mac OS X Unix (LF)
Mac OS 9 (CR)
Scale

Set the default scale factor for the IGES type. The number must be bigger than zero. In most cases, this number should be 1.

Points and Curves

Point Objects
116 (Separate points)

Exports points as separate IGES point entities

106-2 (Layer set points)

Exports points on a single layer as a single point set.

Max degree
No limit

No limit to the degree is applied.

3

All NURBS curves with any degree higher than three are approximated with non-rational cubics to the specified IGES tolerance.

5

All NURBS curves with degree higher than five are approximated, in non-rational quintics to the specified IGES tolerance.

Composite curves as single B-spline

Curve made from two or more B-splines can be exported as an IGES 102 (composite curve) entity or as IGES 126 entities.

Use simple entities when possible

Use this setting to export NURBS curves that are lines, arcs, or circles (within the IGES tolerance) as IGES lines, IGES arcs, or IGES circles.

Fit rational curves

With this setting all rational curves (curve objects and trim curves) are approximated, in non-rational cubics, to the tolerance specified as the IGES tolerance.

Clamp end knots

With this setting periodic NURBS curves are exported as NURBS curves with clamped end knots.

Surfaces

Solids
Separate surfaces
184
186 (Manifold BRep)
402-7 (Unordered group)
Polysurfaces
Separate surfaces
402-7 (Unordered group)
Surfaces
143
144
128 + 3D Trim curves

IGES 128 means all trimmed surfaces are exported as untrimmed surfaces.

Use simple entities when possible

With this setting NURBS surfaces that are planar (within the tolerance specified as the IGES tolerance) export as IGES planes or IGES trimmed planes.

Fit rational surfaces

With this setting, when possible, rational NURBS surfaces are be approximated with non-rational cubics to the tolerance specified as the IGES tolerance.

Clamp end knots

With this setting periodic NURBS surfaces are exported as NURBS surfaces with clamped end knots.

Split closed surfaces

If a surface is closed (like a cylinder), the surface will be split into two halves in the IGES file. If a surface is closed in both directions (like a torus), the surface will be split into four quarters in the IGES file.

Split bipolar surfaces

If a surface has poles at both ends (like a sphere), the surface is split so each half has just one pole.

IGES Export Types

IGES Type

Lists the currently defined IGES types.

New

Opens the IGES Type Details dialog box.

Copy Type

Opens the IGES Type Details dialog box with settings from the currently selected IGES type.

Edit

Opens the IGES Type Details dialog box to edit settings from the currently selected IGES type.

Delete

Deletes the currently selected IGES type.

Related commands

ReadEveryIGESEntity

Toolbar Menu

Not on toolbars.

Not on menus.

The ReadEveryIGESEntity command imports all IGES entities, regardless of type.

Steps

  1. Open the questionable IGES file.
  2. If there is any geometry at all in the IGES file, It will be read. You might, however, get lots of geometry you didn't want and have to dig through the pile to find the items you need.

The ReadEveryIGESEntity command only effects the next IGES file that is read. If you do something like:

open alpha.igs
ReadEveryIgesEntity
open beta.igs
open gamma.igs

Rhino attempts to read every entity only from beta.igs.

Rhino reads alpha.igs and gamma.igs normally, accepting only entities marked as geometry.

IGESStudy

Toolbar Menu

Not on toolbars.

Not on menus.

The IGESStudy command examines specific entities in an IGES file by limiting which portions of the IGES folder are parsed.

Warning

This command is for users familiar with the structure of IGES data files. No technical support is available for this command. The IGESStudy command is for expert users who need to dig through large IGES files on piece at a time. Again, expert knowledge of IGES file structure is required.

Background

Every entry into an IGES file also has folder entry (DE). The information that a DE stores determines if the corresponding IGES entity (curve, surface, solid, color, layer name, etc.) gets read. To further understand the importance of not blindly reading every entity in an IGES file as a top level piece of geometry, do this test:

Steps

  1. Use the BooleanUnion command to make a multi-faced solid from a box, torus, and sphere.
  2. Export the solid to an IGES file.
  3. Read the IGES file back in. You will get an exploded version of what you started with.
  4. Delete all the stuff you just read in.
  5. Run the ReadEveryIGESEntity command.
  6. Read the IGES file again. You will get lots of extra curves and surfaces.
    The extra curves and surfaces you got in step 6 provide the information you need to create trimmed surfaces. These curves and surfaces were imported in step 6 because the IGES reader ignored to DE information that flags the corresponding entity as a part of some "top" level object. The ReadEveryIGESEntity command is used as a last resort to get information out of IGES files that have "top" level objects that have been flagged as parts.

Basic scenario:

You read an IGES file and it looks like some information is coming in damaged. The first thing you need to find out is the DE of the damaged objects. Run the IGESStudy command and turn the Label option on.

IGES debugging options (DEtest=Off FirstDE=1 LastDE=0 ReadEveryEntity=Off Label=On)

Read the file again. This time, every object you read has its Rhino name set to "DE N", where "N" is an odd number. The folder entries in an IGES file are labeled 1, 3, 5, 7, and so on. Select the bad objects and make a list of the DE's that are troublesome. Let us say 13, 137, and 9025 were coming in as bad objects.

Now you use the IGESStudy command to read just the problem entitles, one at a time.

IGES debugging options (DEtest=On FirstDE=13 LastDE=13 ReadEveryEntity=Off Label=On)

You verify that DE 13 is coming in as junk. Then, look at the IGES file (in a text editor or a program like IGESure) and see what DE 13 is supposed to be. If you understand the entity, you can use the IGESStudy command to read in the parts that are used to make the entity. For example, you can look at the base surface and trimming curves to see what might be going on. As you do this, you will find blocks of entities you need to read. In those cases, you can use the IGESStudy command to read chunks of the file. For example:

IGES debugging options (DEtest=On FirstDE=123 LastDE=199 ReadEveryEntity=On Label=On)

will read every entry with DE number between 123 and 199. If you only want to read top level entities you set ReadEveryEntity=Off.

SetIGESLayerLevelMap

Toolbar Menu

Not on toolbars.

Not on menus.

The SetIGESLayerLevelMap command controls the correspondence between Rhino layers and IGES levels on IGES import and export from the command line or a script.

IGES "levels" are like Rhino layers, except they use a number as an identifier instead of a text name. If you have layer standards for products that use IGES to exchange data, you will need a way to define a correspondence between Rhino layer names and IGES level numbers. Rhino has a layer to level function.

To set up correspondence between Rhino layers and IGES levels:

Steps

  1. Select the map file you created.
  2. Select the flavor option.
    For example, if your file is called "iges_level_mapping.txt" and you want to use the "FruitStand" type, set the Flavor option to FruitStand.
Flavor options

LayerMapping

 

Flavor

 

File

 

Note

See also

Import and export objects

Troubleshooting IGES Files with Rhinoceros

Wikipedia: IGES

 

 

 

Rhinoceros 6 © 2010-2019 Robert McNeel & Associates. 19-Aug-2019