Stella Version History

Stella 4.4, 11th January 2008

Changes affecting Small Stella, Great Stella and Stella4D:

• Main reason for this release is that I have changed email and website, so links in the program have been updated accordingly. Please update your links too if you have any.
  OLD: http://web.aanet.com.au/robertw/Stella.html
  NEW: http://www.software3d.com/Stella.php
  Note that all extensions have changed from .html to .php too.

Changes to Great Stella and Stella4D:

• "Scale->Non-Uniform Scale" now has option to keep colours.

Stella 4.3, 2nd November 2007

Changes affecting Small Stella, Great Stella and Stella4D:

• Images:
  • Improved anti-aliasing (smoothness) of textures (eg images on faces and metallic rods).
  • New improved reflection map for metallic rods/spheres.
  • Support for more image formats.

Changes to Great Stella and Stella4D:

• Augmentation improvements:
  • New pyramid height options:
    • Touch model radius
    • New edge lengths = 1
    • Height = 1
  • New prism height option:
    • Height = 1
  • Scale factor for augmentation height when using pyramid/prism/antiprism/cupola. Generally this scales the height directly, but for the pyramid options "Keep edges same length" and "New edge lengths = 1" the edge length is scaled, and for "Touch model radius" the radius used is scaled.
  • Added new coloring option when augmenting or putting models on faces: use any single new color. Saves time choosing new colors each time when performing a series of such operations.
• Fixed crash when creating nets for some obscure polyhedra (those with inversion symmetry only and faces in a plane through the centre of the model, where the stellation diagram has an open area at its centre rather than a vertex).

Stella 4.2, 27th June 2007

Changes to Great Stella and Stella4D:

• Added "Display->Show Vertex Angles". Shows useful angles for users making ball & stick models. Works best for convex shapes.
• Fixed spheres/cylinders not always being exported to POV-Ray.

Stella 4.1.1, 8th May 2007

Changes affecting Small Stella, Great Stella and Stella4D:

• Fixed inability to open some old .stel files.

Changes affecting Great Stella and Stella4D:

• Fixes for "Stellation->Stellation Planes":
  • Fixed: would sometimes hang.
  • Made the operation undoable.
  • Fixed memory leak.

Stella 4.1, 24th March 2007

Changes affecting Small Stella, Great Stella and Stella4D:

• Full screen mode!: "View->Full Screen" or hit F2.
• CHANGED: Left/Right arrow keys now act differently depending on the active view. They now behave like the yellow arrow buttons in views that have them, but still move to next/previous model in other views. You can use Ctrl+Left/Right for the old functionality (always go to next/previous model).
• Show whether polyhedron is convex in Info window. Also moved orientability to this line (was too hard to see before).

Changes affecting Great Stella and Stella4D:

• Inherit colours when creating 3D or 4D convex hulls if there are faces/cells in common. Also maintain colours when creating 4D convex cores (already happened in 3D) [4D applies to Stella4D only].
• Ask before changing to next/previous models if in the middle of faceting (was too easy to do by accident).
• Fixed stellation not working properly for some rare models.
• Fixed convex hulls not working in some cases (3D & 4D).
• Fixed: sometimes lines in faceting diagram would all appear white.
• Fixed loading colours from OFF files in some cases.
• Fixed scaling when putting models on vertices with "Same size as base part".

Changes affecting Stella4D:

• After Ctrl+N (or "File->Polyhedron List"), you may enter the number of a 4D uniform polytope directly (previously you had to put "-" first). This means you can no longer enter a number directly to choose a 3D uniform polyhedron in Maeder order, now "U" or "M" must appear before the number.
• Added "4D->When Hiding Cells, Hide Vertices/Edges Too", to avoid the huge tangle of edges when studying a few cells projected into 3D.
• Overall scale was changed when converting from a 4D projection to a 3D model, now it is kept (orientation is now also kept).
• When selecting a 4D projection direction from the menu with a non-4D view active (eg 3D net), apply projection to another view instead.
• Made the default to hide front cells in 4D. It's confusing at times otherwise.
• Couldn't export DXF, Pov, or triangulated versions from 4D views.
• Fixed errors when converting 4D projection to 3D model with front cells hidden and other cells hidden manually.
• Had uniform polychoron 1150 wrong. Have fixed it (and possibly others).

Cross-sections of various polyhedra

Stella 4.0, 13th March 2007

Changes affecting Small Stella, Great Stella, and Stella4D:

• View 2D cross-sections of polyhedra.
  • Interactively change the slicing depth in real time.
  • Slice along a symmetry axis, or face-first or vertex-first.
  • Interactively rotate the slicing plane.
  • See how the cross-section fits into the original 3D polyhedron.
  • Snap the cross-section depth to the nearest vertex, and step through the depths where the plane hits a vertex.
  • Show small circles when true vertices are close to the slicing plane.
  • Cross-section areas are coloured by averaging the colours of the faces represented by each surrounding edge, with colours from overlapping areas being blended. This gives appealing results, especially during animation.
  • Models may have their faces (or cells in Stella4D) coloured differently along the slicing plane. This makes more colourful cross-sections.
• Added "View->Camera" submenu. Lets you save and recall different viewpoints.
• Added "Display->Show/Hide Faces in Selected Plane".
• Added "Display->Show/Hide One Part of Compound".
• Added "Options->Keep Layout when Opening Files" to keep current layout when opening new files.

Changes affecting Great Stella and Stella4D:

Overlapping colours blend

• Advanced options for colouring areas where coplanar faces overlap. By default the colours are blended. See "Display->Polygon-Filling Options". (Note: nets will still treat coplanar parts as all one colour).
• New augmentation options:
  • Keep coincident faces where parts are attached.
  • Augmentation with a gap. Use Ctrl+Shift+Left-drag to adjust the size of the gap, or Ctrl+Shift+Right-click to snap the gap closed again.
  • Can now preview augmentations using a combination of wire-frame and solid, which is now used by default. Just using solid for previews looked too much like the finished model and it was easy to forget that it was only a preview.
  • Fixed issues when an augmentation has faces coincident with faces of the original model AND faces of other augmentations. Eg extracting J2 or J5 from itself at the triangles (and with a twist).
• When adding from memory, importing a model, augmenting a model or creating a faceted model, edges between coplanar faces can be automatically blended out.
• When using faceting mode on the stellation diagram, edges from faces created so far are highlighted in the same way as in the faceting preview (showing unmatched edges as green etc). Makes it a lot easier to see how your stellation is coming along if you create the faces in this way.
• Added "Poly->Create Convex Core". Works even when model is too complex to be stellated.
• Choose a centre for reciprocation from the following:
  • Centroid of vertices (previously the only option).
  • Centroid of edge-midpoints, or equivalently, a weighted average of vertex positions (weighted by number of incident edges).
  • Circumcentre.
• When the face-types or vertex-types section is open in the Info window, you may click on one of the entries to select a face/vertex of that type. Similarly, when you select a face/vertex some other way, the matching type is highlighted in the Info window.
• Added "Poly->Try to Make Faces Regular".
• Symbols entered in the "File->Polyhedron List" window can now also match with names of files in the Stella library. Eg enter "Bruckner 29,2", or in Stella4D enter "gaghi" to load that 4D polytope.
• "File->Export Image" dialog box has been revamped. Now includes a drop-down list of recently used folders for quickly saving to common destinations, and another drop-down list of image types. There are new options to hide text during rendering, to fit the model either tightly or with space for rotation, and to include some space around the model.
• Made "Poly->Delete One Part of Compound" much faster for complex models.
• Convex hulls of partially complete facetings can now be taken (I think this used to work but broke somewhere along the way).
• Stereoscopic viewing with red/blue glasses works better now when displaying spheres and cylinders for vertices and edges. The wood material in particular didn't come out well before.
• Increased distance mouse must be from vertex/edge to select them (eg for faceting), making them easier to select.
• Ctrl+Shift+Right-click "unexplodes" as before, but a second click will now return to the previous explosion amount. Similar for various other Right-click operations.
• Fixed: Mouse wheel didn't zoom in and out in orthogonal view, only perspective.
• Fixed text getting smaller when exporting an image using over-sampling.
• Fixed: exporting image with face selected would not show face transparently through model properly.
• Fixed: face colours were lost when using "Poly->Project Onto Sphere"
• Fixed rendering problems with various combinations of rainbow mode and 3D-stereo with a selected face or with images on faces in various different view types.
• Fixed: rendering of some complex arrangements of faces with many holes.
• Fixed: When entering a name in "Poly->Polyhedron List" it would sometimes think it was a dual name by mistake and ask if you want to open a dual view.
• Fixed: Crash sometimes when closing Stella while sphere/cylinder options window is still open.
• Fixed: "View->Fit Geometry to View->Tight Fit" would fail for infinite dual models.
• When loading an OFF format file and errors are found, an offer is made to create the convex hull instead.
• 3D DXF files can now be imported, but I fear they generally lack the accuracy required, but it may be useful in some cases.

  Some views of 4D polytopes

Released new product Stella4D:

• Includes all the 3D features from Great Stella, plus support for 4D polytopes.
• Create arbitrary 4D duoprisms and antiduoprisms.
• Includes ALL other 1849 known 4D uniform polytopes. This is the only place you can see all of these.
• Duals are also generated.
• View 4D models projected into 3D (perspective or orthogonal, with or without back-cell or front-cell removal). Interactively rotate the projection direction, or choose cell-first, face-first, edge-first or vertex-first. The default auto setting usually finds the projection giving the greatest symmetry.
• View 3D cross-sections of 4D polytopes.
  • Interactively change the slicing depth in real time.
  • Slice cell-first, face-first, edge-first or vertex-first.
  • Interactively rotate the slicing plane.
  • See how the cross-section fits into the 3D projection of the original 4D model.
  • Snap the cross-section depth to the nearest vertex, and step through the depths where the plane hits a vertex.
  • Show small spheres when true vertices are close to the slicing plane.
• View 3D nets of 4D polytopes. Ctrl+Right click on faces to rearrange the net.
• View 3D vertex figures and individual 3D cells of 4D polytopes.
• You may use the model from any view as the new base model (for creating nets, stellations etc). This includes 3D cross-section, 3D nets, 3D projections of 4D models, 3D vertex figures, or individual 3D cells.
• Truncate, rectify, and expand 4D polytopes.
• Create convex hulls or convex cores of 4D polytopes.
• Delete or keep just one part of a 4D compound.
• Various scaliforms, fissary and compound polytopes are also included, as well as a category which groups all the convex ones together.
• Create 4D prisms from 3D polyhedra.
• When displaying using spheres and cylinders, their size will vary correctly according to the 4D projection (spheres further away in 4D will appear smaller in a perspective projection).
• Most of Great Stella's colouring and hiding options for faces are supported for cells in 4D. Undo/redo, memory slots and Measurement Mode are also supported.