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

From the File menu, click Open or Import.

In the Open dialog box, select the supported file type.

If the import can be configured, click Options to specify import settings.

Click Open, or press Enter.

Note: When Rhino opens a non-3dm model, the title bar reflects the name of the model that was opened. When the model is saved for the first time, this model name is entered as the file name.

Export

To save as or export a Rhino model

From the File menu, click Export Selected or Save As.

In the dialog box, the Files of type list displays the currently supported file types for export.

In the Files of type box, select the supported file type.

In the File name box, select or type a file name.

Specify what is to be saved.

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.

If the export can be configured, click Options to specify export settings.

If the file type creates only mesh objects, in the Polygon Mesh Objects dialog box, specify the mesh settings.

Import notes

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When Rhino reads an IGES file using the Open command, the Rhino units are set to those in the IGES file and the Rhino system tolerance is set to the IGES file tolerance, with some adjustments made to keep Rhino from setting a too small/big tolerance based on a bogus IGES file tolerance.

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When Rhino reads an IGES file using the Import command, the Rhino system tolerance is not changed. The tolerance used in rebuilding incorrect IGES trims is automatically computed and is always smaller than or equal to the Rhino system tolerance. If the IGES units do not match the Rhino units, you are given the option of scaling the imported IGES geometry so that it matches the current Rhino unit system.

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Polygon meshes are not exported to IGES file.

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IGES supports only the printable subset of ASCII characters from character 32 to 127. This causes layer names to be truncated at the first occurrence of a non US character (like é).

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Unnecessary knots are removed from imported curves if the curve has identical geometry and parameterization.

To turn the message back on

Click Options in the appropriate Save, Export, Open, Import, or Insert dialog box.

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

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

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

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

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.

To turn the message back on

Click Options in the appropriate Save, Export, Open, Import, or Insert dialog box.

Export note: There are two types of solids modelers: surfaces and solids. Use the "surfaces" type when exporting a single surface to those products. Use the "solids" type when exporting anything you want to be able to join back together.

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

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

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

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

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

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.

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.

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

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

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

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

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.

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

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

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

ReadEveryIGESEntity

Steps

Open the questionable IGES file.

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:

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

IGESStudy

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.

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

Use the BooleanUnion command to make a multi-faced solid from a box, torus, and sphere.

Export the solid to an IGES file.

Read the IGES file back in. You will get an exploded version of what you started with.

Delete all the stuff you just read in.

Run the ReadEveryIGESEntity command.

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.

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

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:

Create a text file like the following example:
;IGES level translation rules
[3Stooges]
"Default" = 0
"Larry" = 13
"Curley" = 7
"Moe" = 32000

[FruitStand]
"Default" = 0
"Orange" = 9876
"Apple - Delicious" = 13
"Apple - Granny Smith" = 7232
"Grape" = 1

This file defines rules for mapping Rhino layers to IGES level numbers that will be used during IGES export and for mapping IGES level numbers to Rhino layers that will be used during IGES import.

This example file defines two sets of Rhino layer-IGES level correspondence rules (flavors) named "3Stooges" and "FruitStand."

Steps

Select the map file you created.

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

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In general, it is a good idea for Rhino's "Default" layer to correspond to IGES's level 0, but this is not required.

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This file can contain multiple flavors. A flavor has a name enclosed in square brackets [] followed by lines that look like:

"<RhinoLayerName>" = N

where N is a non-negative integer (0, 1, 2, 3, ... ).

The Rhino layer name appears between the quotation marks.

A flavor is terminated by a blank line.

The converter/map program ignores spaces and tabs.

The converter/map program ignores lines that begin with semi-colon (;).

If an imported IGES file contains a level number that is not listed in the set of rules and does have a IGES level name, that level will automatically import to a layer called "IGES_LEVEL_N".

If an exported Rhino layer name is not listed in the set of rules, an IGES level number is automatically selected.