Optical Elements Addon for Blender
OptiCore is a Blender-addon to provide accurate and well-defined models of optical elements (lenses, mirrors, ...) as well as optimechanical components (optical bench, posts, ...). These models can not only help you to easily create renderings of optical laboratory experiments, but also stunning images involving caustics.
Introduction Video on YouTube:
The addon was motivated by the need to create accurate optical lenses. Modelling them in Blender via a boolean operation on spheres can lead to artifacts for low f-number surfaces unless very high (u,v)-number spheress are used, making the computation very slow. The name Opti"Core" is derived from the LuxCoreRender engine, which is a great tool for physically accurate rendering, and also available as a powerful addon for Blender.
You can find a brief description of the available optical elements below. Please don't hesitate to contact me or open a GitHub-Issue if you have any feature requests.
For correct optical behaviour, all elements created with this addon should have smooth shading applied, together with the edge-split modifier, auto-smooth mesh or custom split normals. There appear to be differences between these methods, and I still have to figure out which offers the best behaviour. (Input and user feedback are welcome!)
Creates an optical lens with two flat, spherical or apsheric surfaces. Set surface radius = 0 for a flat surface.
The component origin is placed at the on-axis intersection with surface 1.
Aspheric surfaces are defined with a conical constant and three coefficients for polynominal terms. See the respective Wikipedia-page for an explanation: https://en.wikipedia.org/wiki/Aspheric_lens
An option exists to create a cross-section model (D-shaped lens).
Creates a optical lens mesh with a quadratic outline.
The feature set is currently reduces comapred to regular lenses, i.e. spherical surfaces only and no option for a cross-section model.
Creates an optical mirror mesh with a circular outline, spherical or parabolic surface and a flat back.
Parabolic Mirrors can be constructed with component origin at the focal point or mirror centre. For spherical mirrors, only the mirror centre is available at the moment.
Parabolic mirrors can be constructed as off-axis parabolic mirrors.
A hole along the collimated beam axis can be included.
Creates an array of cubecorner retroreflectors.
Features two "Retroreflector types":
- "Cubecorner", which is how reflectors are typically manufactured, and
- "Trirectangular tetrahedron", which is basically only the lower half. (Uncommon, but why not have it, looks cool...)
Retroreflectors can be used in two ways:
- with a mirror material, in which case you look directly onto the cubes.
- with a glass/plastic material, in which case you look from the flat side. Retroreflection then occurs due to total internal reflection.
A "Tip offset" can be specified to apply an offset to the base bottom vertices of the cube-corners. The range of [-1,1] corresponds to 5% of the "CubeCorner Spacing". This allows to mimic by-design imperfections of retroreflectors for traffic use - if they were perfect, light would be reflected from headlights back into headlight and not reach the human eye.
Hint: slightly bevel all edges to give a realistic segemented look due to real imperfections of sharp corners.
Creates a Siemens Star, a typical MTF or contrast test object.
The structure can be created open ended, or surrounded by a solid cylinder wall and the Siemens Star cut out as a negative Structure.
Creates a rectangular plate with beveled holes and rounded corners, i.e. the top-plate of an optical table.
Upon creation, the faces inside the holes are pre-selected. This allows you to easily assign a second material, e.g. to create a screw thread by shader.
Creates an 0.5-inch optical post (Thorlabs-style), with a 4 mm hole at the top and 6 mm hole at the bottom, as well as a through hole.
Warning: This mesh geometry with a through-hole appears to be very complicated to properly shade smooth. Artifacts may occur with high glossiness. Autosmooth appears to work better than split normals.
Other post-sizes are to follow.
- flat annulus around concave lens surfaces
- elliptics (off-axis flat mirrors)
- Prisms (right-angle, triangle, dove, roof, cats-eye-RR, penta, wedge[?])
- cylindrical lenses/mirrors
- Fresnel lenses
- wedged window
- Axicons/laser line generators
- Further types of aspheric surfaces -- Schmidt corrector plate -- free-form with input formula; if feasible
- Microlens array (test if at all usable with 32bit rendering)
- doublets/triplets with well-defined interior surface
- All: Consistent default settings of size, i.e. mm vs m scale
- Lens: center thickness checks: small surface radii as well as aspheric
- Lens: If faces touch, don't generate one outer rim to avoid duplicate vertices and split-normals
- Lens: Origin at focus point (at least infinity focus)
- Mirror: along-focus holes for OAPs
- CC-RR: manufacturing-accurate closure at sides
- CC-RR: Include Bevel option
- CC-RR: Tip offset presets
- Cross-section models (D-shaped - done for regular lens), perhaps with variable cut width
- lens file import (seq, zmx, spd - open standards? patents? copyright?)
- lens system designer GUI
- split-normals vs. edge-split artefacts
- general limitations of 32bit ray tracing