mirror and OBJ/STP files

[dayeggpi]

Hi Matt,

After years of playing with your code, putting it on hold, playing again, back to my "todo list" and so on, i finally decided to make this happen once and for all coz I'm totally still in love with it since I discovered your work. I don't have extended knowledge as here https://github.com/MattFerraro/causticsEngineering/issues/10, and my project is smaller, but still I really want to make at least two small objects with your code : one in acrylic, and one in brass/mirror style.

1- do you know what would need to be changed (if anything), to make this also work in "reflexion" (i.e. mirror) vs right now as a lens (transparent acrylic) ? or is it just having the light being closer or further away ? I think it was mentioned in this post (in the middle) https://github.com/MattFerraro/causticsEngineering/issues/10#issuecomment-915400762 so I'm not the only one who thought about it, but I am wondering if there is anything in particular to adjust ?

2- I am able to generate the OBJ file, and want to try a simple test on acrylic, but every vendor/service I ask need a STEP/STP file. I somehow manage to convert it to STP/STEP (doesnt work with all softwares, sometimes output us just a few kb....) but the vendor can't open the file (maybe due to the caveats you mentioned in your blog ? or due to the fact that their are too many facets and it just doesnt work ?) So I wanted to know what to do with the OBJ file if I don't have a CNC at home ? Do you have any idea of what can be done to be able to use your code for actual manufacturing, cause right now, not much can be done with the OBJ file unfortunately, which is quite sad knowing the quality of your code (I played with Blender and it works so well I am amazed ! )

Your help would be really precious here and much appreciated (I know it's been 4years)

[MattFerraro]

Hello!

1. The approach in this repo is fundamentally limited in that it only works in refraction. I don't think it can be extended to work in reflection at all. If you need to do reflection, I'd recommend an approach based on optimal transport mapping, such as this one. It will still need to be modified to work in reflection, but at least with that approach it is possible.
2. Unfortunately STEP files just aren't designed to contain triangle meshes. Many manufacturers can actually work with triangle meshes but you might need to get someone on the phone instead of using the automated ordering tools. These caustic lenses are actually quite easy for a manufacturer to cut (3 axis only, acrylic), you just have to help them understand that fact.

Matt