Reference/Release Notes/2.90/Python API

Blender 2.90: Python API


Operator Search

With the new operator search that only searches through menus, add-ons that expose operators only through search need to be updated. In general it is good practice to always expose operators through menus so users can find them.

For more obscure operators that are for example intended mainly for developers, we recommend adding them in the TOPBAR_MT_app_system menu. This is accessible through the System menu under the Blender icon in the top bar.

Other Changes

  • Libraries: relative_remap boolean argument has been replaced by path_remap enumeration which can select different kinds of path remapping on write.
  • BevelModifier.use_custom_profile property is now part of a new a profile_type enum. (6703c7f7f1) This applies to the bevel tool as well.
  • The bevel operator's vertex_only property was changed to a new affect enum, with VERTICES and EDGES options. (4aa2a5481c)
  • The modifier apply operator's apply_as argument was moved to a new operator modifier_apply_as_shapekey. The new operator can also save to a shapekey without removing the modifier (01c8aa12a1)

User Interface

  • Columns and rows can now group together related settings with a heading. For example:
    Release notes layout headings.png
    col = layout.column(heading="Tooltips")
    col.prop(view, "show_tooltips")
    col.prop(view, "show_tooltips_python")
    The layout system will try to insert the heading to the left column of a property split layout, but may insert the heading as usual column or row item as fallback.
  • UILayout.prop_decorator(data, property, index=-1) got added to allow manual insertion of decorators (to set keyframes or indicate other animation states for the property). There must be an item with the same parameters within the root layout for this to work.
  • Checkboxes respect UILayout.use_property_split now. With that some layout conventions changed:
    • Related checkboxes should be grouped together in a column with a heading (see above).
    • In cases where a checkbox controls the availability of a single property, the checkbox should be in a row together with the property:
      Release notes properties checkbox subpanel.png
      Decorator items have to be manually inserted with some boilerplate code, which looks like this:
      row = layout.row(align=True, heading="Auto Smooth")
      row.use_property_decorate = False # Don't automatically insert decorators.
      sub = row.row(align=True)
      sub.prop(mesh, "use_auto_smooth", text="")
      subsub = sub.row(align=True) = mesh.use_auto_smooth and not mesh.has_custom_normals
      subsub.prop(mesh, "auto_smooth_angle", text="")
      row.prop_decorator(mesh, "auto_smooth_angle")
      It is important that the decorator is inserted to a row-layout that is the parent of the row-layout for the checkbox and the actual property.
    • Checkboxes with property splitting often look bad if placed alone in a layout, or within flow layouts. In these cases UILayout.use_property_split should be disabled or a fixed, non-flow layout be used.
  •, UILayout.operator_menu_enum() and UILayout.prop_menu_enum() respect UILayout.use_property_split now.


  • In the event a Python script causes Blender to crash, Blender's crash log will include a Python stack-trace so Python developers can find what caused the error (e9c4325515).
  • Mathutils: element-wise multiplication for vectors matrices and quaternions (fa7ace2215).
  • constraints.copy() methods for objects and bones to duplicate a constraint with all its settings, including from other objects. (64a584b38a)
  • Screen.is_scrubbing, indicating when the user is scrubbing through time in the timeline, dopesheet, graph editor, etc. (2be7a11e43)
  • Sequences.new_movie() support for creating movie strips with missing files, consistent with image and sound strips. MovieSequence.reload_if_needed() to try and reload movie strips, in case the missing file has appeared. This makes it possible to create a movie strip for video files that are synced between computers via some network connection. (b9f565881e)
  • Drivers get a depsgraph variable in their local scope. See the Animation-Rigging release notes for more details.
  • New bl_math module with lerp, clamp and smoothstep functions (inspired by GLSL mix, clamp and smoothstep), which are also made available to drivers. (f8cc01595d)
  • Option to use OpenGL context in RenderEngine.render. (52543be9a6)