January 2026 critical fixes

Bug 100374: The convection to environment constraint produces unexpected results when selected elements cannot convect from their bottom side and the ‘Convect From’ option is set to ‘Bottom’ or ‘Top and Bottom’

Fixed versions: 2606.0

The behavior of the convection to environment constraint has been corrected for element types that do not support bottom-side convection. Bottom-side convection is now ignored for unsupported elements, with a warning issued to inform the user. If a selection consists entirely of elements without a bottom side, a fatal error is triggered to prevent invalid setups. Mixed selections are handled consistently, applying bottom-side convection only to elements that support it.

Bug 100375: The simple radiation to environment constraint produces unexpected results when selected elements cannot radiate from their bottom side and the ‘Radiation From’ option is set to ‘Bottom’ or ‘Top and Bottom’

Fixed versions: 2606.0

The behavior of the simple radiation to environment constraint has been corrected for element types that do not support bottom-side radiation. Bottom-side radiation is now ignored for unsupported elements, with a warning issued to inform the user. If a selection consists entirely of elements without a bottom side, a fatal error is triggered to prevent invalid setups. Mixed selections are handled consistently, applying bottom-side radiation only to elements that support it.

Bug 116911: Different results may be obtained between the finite volume and finite element methods for co-simulation convective loads with thermal streams

During co-simulation runs involving thermal stream loads referenced through co-simulation interface simulation objects, accessible via the Activates the Convective Load Co-simulation Interface for thermal-structural analysis early access feature in Simcenter 3D, a solver defect may lead to incorrect results when using either the finite volume method or the finite element method. As a consequence, key outputs such as convection coefficients, mass flows, and temperatures may be inaccurate.

Bug 117560: Different results may be obtained between the finite volume and finite element methods for co-simulation convective loads with thermal voids

Fixed versions: 2606.0, 2512.3

During co-simulation runs involving thermal void loads referenced through co-simulation interface simulation objects, accessible via the Activates the Convective Load Co-simulation Interface for thermal-structural analysis early access feature in Simcenter 3D, a solver defect may lead to incorrect results when using either the finite volume method or the finite element method. As a consequence, key outputs such as convection coefficients and temperatures may be inaccurate.

Bug 119383: The parallel thermal solver with the finite element method may produce incorrect temperatures for radiation when multiple processors are used

This issue occurred when running radiation analyses with the finite element method in parallel using multiple processors. The problem does not affect the finite volume method, and parallel performance support for the finite element method remains a work in progress. The defect could lead to incorrect temperature results or linear solver instabilities, particularly at the preconditioner level. This fix ensures stable factorization in the parallel linear solver preconditioner and delivers consistent thermal results across all parallel configurations.