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Tutorial: PolyNURB from FEM File

(Made with Altair Inspire)

(Updated by Nimisha Srivastava)

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Obtaining Iso file from Hypermesh Post Optimization

The steps for running an optimization and obtaining an Iso file are given below.

1. Import Geometry:

The first step to start an optimization run is to import the geometry which needs to be

optimized to obtain the final design.

• Select File > Open.

• Select the file 1_set_up.hm

Figure 1 Opening the model

2. Run Optimization:

• Go to Analysis PageOptistruct

• Verify Export options is set to all and Run is set to Optimization

• Click Save as to save the .fem file in the desired location

It is good practice to create a separate folder for the Run to save .fem file

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Figure 2 Opening the analysis page

• Click on OptiStruct.

Figure 3 Selecting export options

3. Open HyperView and view results

1. Message will be displayed as:

OPTIMIZATION HAS CONVERGED FEASIBLE DESIGN (ALLCONSTRAINTS CONVERGED)

Figure 4 Message post completion of optimization

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2. Click Close

3. Select the HyperView option in the tab that is present in the lower half of the window.

Figure 5 Select HyperView

• Once HyperView opens, click on the Iso from the Visualization Toolbar

• Click Apply.

Figure 6 Click on apply to enable changes

• Adjust the value of iso, such that the Model is completely connected. 0.3 value appears

to be a good value for Iso.

4. Generate Iso Model

• Go to Post PageOSSmooth

• Use entity selector to select Use current

• Verify all the selections are same as shown in the figure and threshold is set to 0.3

• Click open icon and select the 1_set_up.sh file

• Click OSSmooth.

Figure 7 Click OSSmooth

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5. View and Locate Iso file

• The 0.3 Iso is applied on the model as shown in figure.

• The Iso file named as 1_set_up_oss.fem is generated in the same location

where the Hypermesh Model (1_set_up_oss.hm) is stored.

Figure 8 Iso 0.3 model

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Creating PolyNURBS from .fem file in Inspire

1. Importing the model:

• First, ensure that the MKS (m kg N s) unit system is activated by entering the File >

Preferences > Units to ‘m Kg N s’.

Figure 9 Setting the unit System

• Alternatively, use the dialogue at the bottom right hand corner

Figure 10 Tab for Changing Units

Tab for changing units

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• Select the File> Import option. Select the file 1_set_up_oss.fem

Figure 11 Importing the file

• Select the two parts and press H to hide or Select the two parts in

the Model Browser and right click and hide.

Figure 12 Hiding 2 parts

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Figure 13 Model after hiding two parts

• Select Polynurbs located in the Ribbon in Geometry

Figure 14 PolyNURBS icon

• Click Create and select the part to create a part to surround with cage.

Figure 15 Create cage around the part

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• Click Sharpen from the Polynurbs and click on the face twice to sharpen it more.

Figure 16 Sharpening the PolyNURB face

• Repeat the same process for all the faces.

Figure 17 The part after sharpening all the faces of the PolyNURB

• Now, hide this part and the design space to create a PolyNURB around the second

non-design space.

• Show the part from the Model Browser

Figure 18 Part to be shown

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• Create PolyNURB part to surround with cage.

• Sharpen all the faces.

Figure 19 Creating PolyNURB part

Figure 20 Sharpening all faces

• Next, we will create PolyNURBS around the design space.

• Select the design space part in the Model Browser, right click and select isolate.

Figure 21 Isolating the Design Space

• Click wrap from the PolyNURBS.

• Create a wrap as shown in figure.

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Figure 22 Using wrap to build PolyNURBS

• Similarly create wraps around small sections as shown

Figure 23 Creating the wraps around the small sections

• Select the two faces and click Bridge from Polynurbs

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Figure 24 Bridging PolyNURBS

• Similarly create a bridge between as shown in figure

• If the faces of the PolyNURB is too sharp, press undo and smoothen the face as shown

using Sharpen feature from PolyNURBS, then bridge the two faces again.

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Figure 25 Creating a smooth transition

• Similarly apply smoothening to face wherever required and bridge:

Figure 26 Completing the structure by bridging

• Show the PolyNURBS Block 1 and 2 from the Model Browser by clicking on the box to the

left or right click and press show.

Smooth Transition

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Figure 27 All PolyNURB parts

• Select the face shown and click the Move tool

Figure 28 Select the indicated face

• Pull the translate arrow to extend the selected face. Extend the PolyNURB such that it

intersects the other PolyNURB.

(Intersection is created purposefully to Boolean the two PolyNURBS later)

Figure 29 Extending the selected face

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• Similarly extend the two bottom faces.

Figure 30 Extending the two bottom faces

• Now to create intersection between the PolyNURBS.

• Select Boolean located in the Ribbon in Geometry

• Select the Intersect

• Select the Highlighted Part (Design Space) as Target and the other two PolyNURBS as

Tools.

Figure 31 Steps to create intersection

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• Select Keep Targets and Keep Tools.

• Click Intersect.

• A warning will be displayed as Polynurbs cannot be edited after performing Boolean

Operation.

• Click Continue.

• Now that the PolyNURBS are successfully created, delete the rest of the geometry.

• Save the file into any CAD format.