Importing to BUILD3D: Import from CAD Sources

This tutorial uses GeoStudio 2021.3 and will show you how to import 3D CAD files in the *.step, *.iges, *.dxf, *.dwg, and *.stl file formats.

What’s in this video?
0:00 Introduction
0:30 Three methods for importing CAD files
1:54 CAD File Types – Best Practices
3:26 Import Body in BUILD3D
5:00 Import Background Mesh in BUILD3D
6:47 Import Profiles in BUILD3D

Video Transcript

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<v Instructor>Welcome to the Build3D importing series.</v>

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In this session, I will show you how

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to import files from third party CAD sources

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into Build3D to simplify your geometry creation.

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This workflow is useful

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for creating 3D analysis-ready geometry based on files

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that have been created in CAD software,

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removing the need to recreate the geometry in Build3D.

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There are three methods

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for importing CAD generated geometry into Build3D.

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The first method is importing as 3D solids.

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Three dimensional bodies can be imported directly

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into Build3D if they are in the STP or IGES file format.

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The second method is it importing as background mesh.

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Surface meshes that have been created

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in CAD software can be imported

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as a background mesh in Build3D.

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A background mesh can then be used for 3D sketching

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or for the creation of a nerve surface, such as topography.

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File format supported in this import type

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include DWG, DXF or STL format.

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The last option that I will cover today is importing

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as a 2D or 3D sketch profile.

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This third option for CAD importing is

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through 2D or 3D sketch profiles,

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which are useful or for importing design structures,

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such as embankment cross-sections or tailings dam designs

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into the three dimensional geometry.

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File format supported in this import type

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include STP and IGES format.

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First, let’s talk about the different format types

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that can be exported from CAD software.

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When importing in the STP or IGES format as a solid,

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it is best to ensure

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that the body is a parametric representation.

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For example, consider these three cylinders.

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All three cylinders can be saved to the STP file format.

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However, each have been created in a different way

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and will behave differently when imported into Build3D.

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The red cylinder is a parametric representation.

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It is an extrusion surface consisting

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of three parametric surfaces,

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the bottom, the top and the curve side.

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This is the prefer representation

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of geometry in Build3D.

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The green cylinder is a mesh representation of the surface,

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it contains 50 vertices and 32 faces.

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Build3D cannot import the cylinder as a solid,

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but we will review it during the background mesh portion

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of this video.

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The blue cylinder is a polysurface.

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A polysurface is a faceted nerves structure.

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Build3D will read this representation

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with each mesh face bred as a separate surface.

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With this format,

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you are able to use the geometric operations,

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but it is not a preferred representation.

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Let’s switch to Build3D so that we can import this file

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with three cylinders to further illustrate

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how these different representations are imported.

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In Build3D, we will go to Import Body

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and choose the cylinders.stp file.

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This geometry was created in a third party CAD software

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where the Z coordinate is the elevation parameter.

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Build3D requires as Y coordinate as the elevation,

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so we will first remap the axes using the dropdowns

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before clicking on okay to finish importing the file.

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Here, you can see

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that the parametric representation imported the best

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as it was imported as a single solid

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with three simple faces.

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The mesh representation could not be imported as a body,

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so it doesn’t not show up in the geometry tree.

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Finally,

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although the polysurface cylinder imported as a body,

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there are now multiple faces for the same solid

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in the geometry tree.

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This leads to difficulty

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with defining boundary condition assignments

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and generating a clean mesh without first spending time

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to clean up the solid.

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Now, let’s look at a file

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that was created using the parametric representation.

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We will delete this import step in the design history tree

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and go back to Import Body.

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This time, I will choose the subway.stp file.

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Once the file is remapped to the Y coordinate as elevation,

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you can see that three solids have been imported

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in the tunnel design.

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Now let’s delete that import again.

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Let’s go back to the cylinder file.

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Except this time, we will import it as a background mesh.

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You will see that this time,

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only the green cylinder has been imported

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as it was the only solid recognized as a mesh.

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If the mesh is a structure,

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it can be used with the sketch 2D or sketch 3D commands

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as a snapping object while drawing.

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If the imported file is an open surface,

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such as a topography,

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it is best to import the mesh surface as a background mesh

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in either the STL, DWG or DXF file format.

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Let’s open the ground surface DWG file as an example,

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we will need to remap the axes like we have done previously.

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Now, we can right-click on the mesh

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under the background’s tree and choose Fit to Surface.

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This opens the fit to surface window,

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which will be discussed in the next tutorial video

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of this series.

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The last import feature we will discuss

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in this video is the import profile.

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Let’s switch to a new Build3D project,

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which already has a geological model imported via Central.

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For more information on importing from Central,

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please refer to the previous video of this importing series.

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Now, let’s say we wanted to add a tailings dam design

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that was created in a third party software

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to review the potential poor water pressure conditions

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of the underlying foundation following construction.

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To add this design to our 3D model,

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we will go to Import Profile.

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Here, we will choose the 2D cross-section design

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that was created in a CAD software.

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Once imported, we will need to ensure

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that we remap the axes and insertion point

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to our desired location.

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Once the cross-section is inserted to our desired location,

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we can now convert this profile to a solid

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by extruding it across the geological model.

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If we assume that nothing was removed

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from the original topography

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for the construction of the tailings dam,

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we can cut the solids using the foundation materials.

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We have now reached the end of the session.

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Next time, we will discuss the fit to surface feature

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in Build3D.

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Thank you.