InStep Studio


STL to CAD with InStep Studio:
A Mesh to STEP Converter

The InStep Studio V3.0 application has one (ambitious) goal: be the missing link between converting Polygon Mesh Data to a CAD supported Boundary Representation (in the STEP format). This is most frequently encountered when trying to convert STL files to CAD (using the neutral STEP or STP file format).
Beyond this, the application also allows import and export of Finite Element formats (NAS,BDF,POLY, OUT, GEO) as well as extraction of the surfaces from these formats as sources of CAD bodies. Generally, we consider this application a converter for most Mesh formats to a suitable format for use in CAD.

Please click the buttons below to expand and get more information about the capabilities:

Application Capabilities

InStep Studio 3.0, formerly InStep (and before that simply stl2step) is an application that converts Mesh to CAD files. The most common of these mesh / polygon formats is the STL format. STL files come as both ascii and binary formats with the binary STL files being more compact. OBJ files are also supported (though no materials are imported). The output is to the STEP (.STP) file format with is a very popular, CAD-neutral file format. Below is a brief overview over the capabilities of the application. For more information, please visit the Web Help section and follow the tutorials or download the application and use it for Free* (see below).

File Import/Export

The application can import the following file formats (*: only geometry, +: Some Additional options available):

  • Polygon/Mesh Files: STL (Ascii & Binary), OBJ, PLY, OFF, 3DS
  • Point Clouds (with normals)+: XYZ
  • FE-Geometry: Nastran (.nas, .bdf, .dat), Patran (.out, .neu), ICEM (.poly), Ensight (.geo)

Export of polygon data is to STL (Ascii or Binary selectable), OBJ or STEP


The application contains a very basic option to edit data on a per-triangle basis which is useful for cases where individual facets are corrupted or need changing.
Beyond this, there is a suite of automatic tools to perform common error corrections:

  • Removal of invalid Facets and Duplicate Items
  • Automatic Normal-Vector Correction
  • Boundary-Boundary Stitching and Overlap Splitting
  • Vertex Merging and Hole Closure Tools
  • Some Automatic Repair tools and Surface Wraping

Per-Body Modifications

Data, such as facets and details, can also be altered on a per-body basis. The available tools consist of:

  • Solidify/Thicken Tool
  • Decimating/Simplify Tool
  • Surface Remesher
  • Triangle to Quadrilateral Mesh Conversions
  • Surface Subdivision
  • Surface Splitting (by connectivity or angle)
  • Surface Grouping
  • Boolean operations (Unite,Subtract, Intersect)

Feature Detection

For the case where the imported mesh consists of clean data, describing mechanical and geometric entities, the application allows for a limited recognition of the original shapes and therefore can greatly reduce the resultant file size. Ideally, this is for cases where the data defines things such as simple bodies (blocks, holes, etc.) but it does allow for a certain amount of 'mixed' data.

Reverse Engineering

The Reverse Engineering Tools are a very interesting group of capabilities that are otherwise not available to software packages in this price class.
The available tools fall into one of two classes:

This generates intersection curves that can be exported as either DXF or STEP files (either located in space or projected to the X/Y plane. This is useful for more mechanical designs where sketches are to be used to manually re-create the original data.
The NURBS Surfacing tools allow for shapes that are generally more 'organic' to be converted to Smooth Surfaces (NURBS) that can be read and manipulated in most CAD Applications. This allows data from 3D Scanners that would otherwise be impossible to import into CAD to be easily worked with. Both automatic and manual tools exist to generate the definition for the underlying surface detail.
In general, when we encounter a need for a 'reverse engineering' application, either the Slicing or (NURBS) Surfacing come to mind and it is this capability that most users are looking for.

There are a number of other software solutions operating in this space and we certainly do not claim to be the best* or anything of that sort. However, we offer a very interesting value proposition:

Compare the InStep Studio application in terms of capabilities and you will find that it is capable of working with very large files (unlike Free* applications), can perform feature detection and conversion (FreeCAD, for example, can only do this for flat surfaces), can perform intersection-to-sketch conversions (FreeCAD cannot), and, perhaps most impressive, can perform organic / free-form to smooth NURBS conversions at user selectable resolution.

These kinds of capabilities are - from what we know - only available within high end professional packages such as the Geomagic Design X application which sells at about 100x the price (yes, that is not a typo).

If you need convincing, we simply ask that you give us a try: Create an account for free, download the application & perhaps check out the Tutorials. If you are not convinced that this application is for you, then that is fine, we will never bug you.

Download and Use of the application requires an account. Anyone can Create an Account but note that sharing licenses is not allowed (see EULA). There are several licensing options available:

Free (With Advertising)
The Free License is aimed at evaluating the application and for students. No Commercial activity is permitted under this license. During use, the application will briefly pause and display advertising on an ongoing basis. We reserve the right to make changes in the future whereby we limit the amount of days over which the application can be used with a free license.
Annual License ($99+tax)
This provides access to the application for the period of 1 year.
Perpetual License ($249+tax)
The perpetual license does not expire but annual maintenance (for access to the latest version) is required. Cost includes first year maintenance ($50).
Company Administration/User(s)
The option exists to administer licenses from one account and assign them to other users.

Get more information about available licenses and restrictions from the License Help page.
Note that all purchases are made from within the user's account (from the License page once an option has been selected) using a secure payment process provided through PayPal.

How to Get Started?

If you are new to the application then please create a new account from where you can then also download the application installer:

Please note: the use of an account is purely for loging into the application. We will never spam you (and you have the option to turn off any and all communications).

Media / Examples Gallery

Below are a few example animations of the application in action. Click on any item to see a larger video.