Power SubD-NURBS

Power SubD-NURBS

Use MODO at the front end of your design pipeline to prototype virtually any organic surface

Power SubD-NURBS lets you export Subdivision Surface meshes from MODO into NURBS-based CAD formats that load into a wide range of CAD systems. This tool facilitates use of MODO as a concept modeler at the initial stage of the design process -- where MODO’s ability to quickly create organic shapes is especially useful. With this tool, you can freeform model a variety of design alternatives in MODO and then transfer them to your CAD system for further refinement and engineering.

How does Power SubD-NURBS for MODO fit in the CAD workflow pipeline?

The chart below shows how Power SubD-NURBS for MODO allows you to export models created in MODO and save them out as NURBS surfaces in any of these industry-standard file formats: IGES, Rhino, SAT and STEP.

MODO CAD Workflow Tools enable import and export of CAD files to/from MODO

Click on the chart above to view each of the MODO CAD Workflow Tools.

Power SubD-NURBS Settings

Power SubD-NURBS provides the ability to convert your Sub-D meshes into high quality NURBS surfaces with the following controls and workflow:

Polygonal vs. SubD Faces — The Plug-in can perform two types of exports: either “one-to-one” where each face of the mesh becomes a single planar face in the CAD format, or “smooth” where subdivided faces of the mesh will be combined to define curved NURBS surfaces. Typically the one-to-one export will have many small, sharp edges while the smooth export will generate large, primarily G2 continuous surfaces.

The export accomplishes this by treating each face of the mesh as either polygonal or as a Subdivision Surface based on how the mesh is currently displayed in MODO. It uses the displayed state as a tag for how each face should be processed.

“Power SubD-NURBS for MODO brings my workflow to the next level. I can now combine the freedom of surface subdivision modeling with the superior accuracy of NURBS technology – the best of the two worlds!”

– Pascal Beeckmans

Export a Mesh – The workflow is simple. First select the desired mesh in the scene. Then when you Export As or Save As in MODO, several new CAD formats are presented in a drop-down menu.

Export File Formats

IGES – .igs extension (Initial Graphics Exchange Specification)
Rhino – .3dm extension (McNeel’s openNURBS format)
SAT – .sat extension (ACIS SAT file format)
STEP – .stp extension (ISO 10303, AP 203 format)

Please note that RHINO export is for Windows only.

Subdivision Quality – You have control over the density of the resulting NURBS surfaces when using the Plug-in. The “Medium” setting uses the level that the Plug-in determines to be optimal, but if the resulting quality is too low then using “Fine” or “Very Fine” can improve the results. Alternatively, if only a rough result is needed then “Coarse” can be selected for a faster export.

Edge Detection Angle – The Plug-in uses this angle when determining the surface breakdown of the CAD data. The default value, 145.0 degrees, is usually optimal for organic meshes. In cases where there are weighted edges or fairly sharp angles, the value can be lowered.

Enable Crease Edges – Checking this setting will prevent the Plug-in from trying to smoothly blend the continuity of surfaces that meet at sharp angles. The images below are the export results without and with this setting enabled.

Triangulate Invalid Quads – This setting can improve the results when the mesh contains quads with very extreme angles between edges.

MODO materials – The Plug-in uses MODO materials as part of the criteria for determining the final surface breakdown in order to guarantee that there will be an edge along the boundary between different materials. This feature can be used to force specific edges to be generated for your desired CAD format where the Plug-in would have otherwise determined edges to be unnecessary.

MODO and MoI Example

Sample Project using Power SubD-NURBS

The first example involves the design of a computer mouse. After concept shape modeling in MODO using Subdivision Surfaces, the model was converted to NURBS. Then it was taken into MoI, a 3D Modeling/CAD application, where detailing occurred. Next, the modified model was brought back into MODO for final rendering. Images and workflow by Pascal Beeckmans.

MODO and DS SolidWorks Example 1

Sample Project using Power SubD-NURBS

In this project, a gas tank for a motorcycle is prototyped in MODO using Subdivision Surfaces and then exported as NURBS into SolidWorks. The final result is brought back into MODO for final rendering. Please note that the CAD Loader and PAD products were used in the latter phase. Images and workflow by Paul McCrorey.

MODO and DS SolidWorks Example 2

Sample Project using Power SubD-NURBS

This example was provided by Branden Coker and Paul McCrorey. Here the goal was to produce an ergonomic handgrip for a trekking pole. Various concept designs were modeled quickly using Subdivision Surfaces in MODO, and then the geometry of the preferred design was converted to NURBS. The model was given more details in Solidworks and then rendered as a final result back in MODO. The CAD Loader was used in the final phase.

“Organic NURBS surfacing is no longer strictly the domain of T-Splines! Modeling in MODO and exporting to your CAD package of choice is a powerful workflow. MODO+NURBS; two great tastes that taste great together!”

– Branden Coker

Comparison images from Power SubD-NURBS

The following sets of images show three conversions from Subdivision Surfaces to NURBS as a comparison of surface fidelity on various organic and mechanical models as they were converted from Subdivision Surfaces to NURBS.

Revolver Example

Sample Project using Power SubD-NURBS

Bug Head Sculpture Example

Sample Project using Power SubD-NURBS

Sheep Sculpture Example

Sample Project using Power SubD-NURBS

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