CAD Import

Capture the finest details of your geometry by using a large number of infinitesimally small and densely packed particles.


Parts can be added by importing CAD models. The pre-processor automatically discretizes the parts into equally spaced material points and assigns them their respective attributes as specified by the user. No meshing is required.

MPMsim™ stores models as a collection of parts where each part can have its own unique material properties, material point density, temperature, velocity and acceleration defined as initial conditions independent of all other parts in the model.

Step 1: Select CAD file(s) to import Import CAD Icon

Click on the 'Add Part to Model' icon in the toolbar or click on menu Model-->Add Part (keyboard shortcut: Command + A on MAC or Ctrl + A on Windows).

Select CAD File

Browse to and select the CAD file that needs importing. Multiple CAD files can be imported by Ctrl (or Command) selecting.

A 'part' in MPMsim™ can be a single CAD part in the conventional sense of the term or a collection of CAD parts having similar properties and initial conditions.

Step 2: Define Initial Conditions

Define initial conditions

The 'No. of particles' field determines the discretization density (number of particles per unit dimension) which in turn affects the resolution of deformation.

Duration of acceleration can be defined as a range for e.g. 2 8 means the acceleration will be applied between time is equal to 2 seconds and time is equal to 8 seconds. Specifying one value applies acceleration from time is equal to zero to the specified time. Leaving the duration field blank or typing in "inf" applies the acceleration throughout the simulation.

CAD Model dependent simulation parameters are autofilled by default upon import. Autofill rules are customisable.

1. ASCII and Binary .STL (Stereolithography)

Click here to read more about the .stl file format.

Most CAD packages allow exporting to .stl format. Export as follows:

- Export
-Save As >STL
- Enter File Name
- Save

- Your design must be a three-dimensional solid object to output an STL file.
- Make sure the model is in positive space
-Set Facetres to 10
- At the command prompt type STLOUT
- Select Objects
- Choose Y for Binary
- Choose Filename
- Choose Stereolithography from Export options
- Enter the filename
- Click OK

- Choose Stereolithography from Export options
- Enter the filename
- Click OK

- File >Export >Rapid Prototype File >OK
- Select the Part to be Prototyped
- Select Prototype Device >SLA500.dat >OK
- Set absolute facet deviation to 0.000395
- Select Binary >OK

- Click on File > Save Copy As
- Select STL
- Choose Options > Set to High
- Enter File Name
- Save

- Right Click on the part
- Part Properties >Rendering
- Set Facet Surface Smoothing to 150
- File >Export
- Choose .STL

- Click on File > Save As
- Select the file type STL
- In the Export STL dialog box, set Format to Binary
- Set the Chord Height to .001". The field will be replaced by a minimum acceptable value for the geometry of the model
- Set Angle Control to .5
- Name the file and click the OK button
- Pro/Engineer will save your STL file, and display your triangles on the screen

- File >Save As
- Select File Type >STL
- Enter a name for the STL file.
- Save
- Select Binary STL Files

- File >External >Save STL
- Select Binary mode
- Select Part
- Enter 0.001mm for Max Deviation Distance
- Click OK

- File >Save As
- Set Save As Type to STL
- Options
- Set Conversion Tolerance to 0.001in or 0.0254mm.
- Set Surface Plane Angle to 45.00
- Save

- File >Save As
- Set Save As Type to STL
- Options >Resolution >Fine >OK
- Save

- File >Save As
- Set Save As Type to STL
- Save

- File >Export >Rapid Prototyping
- Set Output type to Binary
- Set Triangle Tolerance to 0.0025
- Set Adjacency Tolerance to 0.12
- Set Auto Normal Gen to On
- Set Normal Display to Off
- Set Triangle Display to On

MPMsim Tutorial: CAD Import


      1. Mac
      2. Linux
      3. Widows
      1. Starting MPMsim
      2. Quitting MPMsim
      1. Activating License
      2. Deactivating License
    1. Overview
    2. CAD Import
    3. Selection Tools
    4. Loading Conditions
    5. Boundary Conditions


Autofill Settings

Know Bugs

  • MPMsim hangs while importing CAD.

    Cause: Out of Memory.

    Workaround: Avoid specifying 'No. of Particles' values that will result in values too large for the available on board RAM.

Future Enhancements

  • CAD Formats

    Support for additional CAD formats.

  • Import Assembly

    Ability to import entire assembly and discretise into individual MPMsim parts.

  • MicroCT Data

    Import and convert Micro CT data into material points.

  • Fluids

    Specialised objects for fluids.

  • Granular Objects

    Specialised objects for granular models such as soil.

  • CAD live links

    Live links to popular CAD packages to automatically update geometry changes.

Contact information

MPMsim Ltd.


83 Ducie Street


M1 2JQ

United Kingdom


skype: MPMsim

email: [email protected]

phone: +44 161 298 1984


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