# Version 3.6

nTopology 3.6 is here! This release features two new blocks that enhance nTopology’s Topology Optimization capabilities: the new Natural Frequency Response (beta) block and the updated Overhang Constraint (beta) block. Also, many significant usage improvements are included in this release: GPU accelerated primitives/blocks, promotion of simulation import blocks to production, transformation support on FE Mesh, Volume Mesh Block update, etc. As with every release, nTopology’s dedicated support team is ready to answer your questions. Please visit support.ntopology.com to gain access to helpful tutorials and support articles.

#### Natural Frequency Response (Beta)

• A new design response for natural frequency has been added to our topology optimization capabilities.
• The Natural Frequency Response (beta) enables a wide range of use cases, including maximization or lower bound constraints on the smallest natural frequency, as well as frequency gap constraints and gap maximization.
• The natural frequency design response f is given as: f = min(|fi - f0|), where fi [Hz] is the i’th closest natural frequency to reference frequency f0. The smallest eigenfrequency response can be retrieved with f0 = 0, whereas band-gap responses around a reference can be constructed with a non-zero f0. More specifically, a band gap constraint prohibiting frequencies in the range [flower, fupper] can be formulated as f > δf with f0 = (fupper + flower)/2, δf = (fupper − flower)/2.
• Location: Beta > Topology Optimization
• Name: Natural Frequency Response (beta)
• Description: For a given set of boundary conditions, construct a design response of the minimum natural frequency, f = min(|fi - f0|), where fi are the lowest natural frequencies (i = 1, .., Number of modes) and f0 is a given offset value.
• Type: Boundary Condition List
• Description: Load case for the design response.
• Input 02: Number of modes
• Type: Integer
• Description: Number of modes that will be searched for and included in the response computation.
• Input 03: Frequency offset
• Type: Scalar
• Description: Frequency offset used in the design response computation.
• Output: Design Response

#### Updated Overhang Constraint (Beta)

• The Overhang Constraint (beta) block has been updated to include two more options enabling more design freedom.
• The first option is to auto-detect boundary facets that will be used as support boundaries for a given build direction. At the same time, the existing “Support boundaries” has been changed to be optional since it is not needed when the “Auto-detect support” option is selected.
• Furthermore, we are introducing an option to include passive regions in the overhang filter. That means that the topology optimization will work towards adding support for those regions as well.
• Location: Beta > Topology Optimization
• Name: Overhang Constraint (beta)
• Description: Setup a maximum overhang constraint for a topology optimization process.
• Input 01: Build direction
• Type: Vector
• Description: Build direction.
• Input 02: Max angle
• Type: Scalar
• Description: Max overhang angle with respect to build plate.
• Input 03: Support boundaries
• Type: FE Boundary List
• Description: Support boundaries which material can be placed onto.
• Input 04: Auto-detect support
• Type: Bool
• Description: Option to automatically detect boundary facets of the design space that will require support for a given print direction and critical overhang angle.
• Input 05: Include passive
• Type: Bool
• Description: Option to include passive regions in the overhang filter evaluation.
• Output: Optimization Constraint
• The following is an Illustrative example, which enforces an overhang constraint with both options enabled: “Auto-detect support” and “Include passive”

#### Usage Improvements

• We have updated the layout and behavior of the settings window to simplify the user experience. Each subset of options now has titles to make them easier to navigate. Plus, we have reduced the number of buttons to confirm the settings. When a change is made, it will update immediately, providing instant feedback. Pressing the Ok button will confirm the change and close the window.

• Primitive geometry types now leverage GPU Acceleration and are interactive. This improvement is applied to the following primitive blocks: Box, Cub, Box from Points, Skewed Box, Cylinder, Cylinder from Line Segments, Sphere, Cone, Torus, and Boundary Box. The following blocks have also been updated to leverage GPU Acceleration in rendering: Cell Map on CAD Face, Cell Map between CAD Face, Cell Map on Quad Mesh. To enable GPU Acceleration, go to File > Settings > General and Enable GPU Acceleration.

• Below is a list of blocks that have been modified to leverage GPU Acceleration but are not interactive. Instead, their results in the form of fields (accessed via the properties tab) do not break downstream interactivity where they are utilized.

• Buckling Analysis
• Modal Analysis
• Nonlinear Thermal Analysis
• Static Analysis
• Thermal Analysis
• Transient Thermal Analysis
• Import CFD Analysis Result
• Import Static Structural Result
• Import Static Thermal Result
• Import Modal Result
• Import Buckling Result
• Import Time Dependent Structural Result
• Import Time Dependent Thermal Result
• We’ve added length as a property to the Curve type. You can access the length by clicking on the Block Information panel, selecting the Properties tab, and expanding the Properties drop-down.

• In nTopology 3.6 we’re promoting the following simulation import blocks from beta to production. These blocks allow you to import simulation results from other software:

• Import CFD Analysis Result
• Import Static Structural Result
• Import Static Thermal Result
• Import Modal Result
• Import Buckling Result
• Import Time Dependent Structural Result
• Import Time Dependent Thermal Result
• Import Topology Optimization Result
• FE Mesh can now convert to a Spatial3D type and transformations can be applied on it: Scale Object, Orient Object, Rotate Object, Transform Object, and Translate Object.

• We are updating the Volume mesh block. You can find the up-to-date block in the simulation ribbon, or by searching for it in the block search bar. The old version 1.0.0 required specifying the element shape of the output mesh (Tetrahedra or Hybrid). The updated version will automatically use tetrahedra or quadrilateral pyramids based on the provided domain. Updating to the new version (1.1.0) will not affect the result. If the block, in version 1.0.0, had thrown an error asking to switch shape, switching to the version 1.1.0 will result in a valid output. Below is an outline of the updated version of the block:

• Location: Simulation > Mesh
• Name: Volume Mesh
• Description: Mesh a solid domain with tetrahedral elements that conform to the boundary of the specified Domain. If the Domain contains quad faces, quadrilateral pyramids will be used. The Remesh Surface block can be used to remesh the boundary Domain if necessary. If the input domain contains defects that cause this block to fail, consider using the Robust Tetrahedral Mesh block.
• Input 01: Domain
• Type: Mesh
• Description: The domain to mesh.
• Input 02: Edge length
• Type: Scalar Field
• Description: The target edge length of the generated elements.
• Input 03: Growth rate
• Type: Scalar
• Description: The rate at which the size of adjacent elements can grow.
• Output: Volume Mesh
• CFD results are now available as properties in the Import CFD Analysis Result block and can be used directly as fields to modify designs. The fields are generated from the FE nodal data using Barycentric interpolation, and the values on the surface nodes are used for extrapolation. The resultant field is more accurate than the traditional point map approach and computationally more efficient. The results contained in the imported CFD file are organized in Dictionary types with the key being a list of names of the results and the values being a list of scalar or vector fields.

• Thermal reaction flux is now available in the HUDs of thermal analysis results (Static Thermal Result and Time Dependent Thermal Result) and as properties that can be used directly as a field to modify designs. The field is generated from the FE nodal data using Barycentric interpolation, and the values on the surface nodes are used for extrapolation.

• New properties have been added to the FE Boundary type in addition to the already existing fe mesh property.

• New properties have been added to the FE Region type.

#### Bug Fixes

• We’ve resolved an issue with the Pattern Repetition Constraint (Beta) where non-symmetric meshes were leading to unexpected results.
• We’ve resolved an issue where the base units were not correct while probing values in the field viewer for complex units of force (N/lbf), and pressure (Pa/psi). In nTopology 3.6, the values, in the field viewer, are followed by the correct complex units, instead of the base units.
• We’ve resolved the issue where you were not able to change the color of face based lattices.
• We’ve resolved an issue where selecting a cell map on the scene was not possible while in Navigate Map.
• We’ve fixed an issue where we were interpreting 2D Implicit Bodies as extrusions.
• We’ve resolved an issue in the Cell Map between CAD Faces block where changing the input parameter Second UV Origin causes the UV coordinates of the second face to flip rather than rotate.

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