3D Surface from Curvature Angles

[Anonymous]

Hello, I'm trying to design a curved, 3D elliptical structure (similar to a contact lens shape) whose upper surface curvature changes in selected locations according to an inputted curvature angle, and the surface curvature between these inputted values can then be averaged. Does anybody know how I can go about this? I have around 12 values. Many thanks.

[SEANT61]

Post the input data. That would be the best way to get pertinent response to this query.

[Anonymous]

Thank you. Please find the data attached - I ultimately want to reconstruct a cornea whose anatomy is defined by all the data in the attachment, and I thought I'd start with the data in the top left box entitled 'Axial/sagittal curvature (Front)' and extend it by imputing thickness values after I've designed this front (or upper) surface. I believe the values written on the image (44.5, 45.8, etc) are in degrees. Is there a way to do this using AutoCAD? Thanks.

[SEANT61]

Yikes!  Lots of information there.  And almost none of it makes any sense to me.  No wonder ophthalmologists make the big bucks.

I had hoped that some of the data could be converted into a heightmap.  I don't suppose that is one of the output options in Pentacam?

[leeminardi · Accepted solution]

First let me say that I have no experience with lens design and I think you should do a lot of research into how the diagrams should be interpreted.  That being said, AutoCAD does include a number of features for creating and analyzing 3D surfaces although the user interface can present some challenges.

Looking at the Elevation image you posted, it appears that the numbers refer to a deviation from some base surface.  I assume + values denote an area where the surface bulges out and - values where the surface has a depression.  Warmer colors indicate a bulge out and cooler colors a depression.  Green indicates an inflection between the two areas and can be assumed to have an instantaneous curvature of infinity (flat).  

You should become familiar with the options on the Surface tab. I created a cross section of a lens, revolved it into a surface and then converted the result to a NURBS. I then moved a couple of the CV's to add complexity to the shape. Using the Analysis Option, you can display the Gaussian, Mean and other curvature characteristics.  

Bottom line?  I think AutoCAD could be used to model the surface and do some analysis but it will require significant effort on your part to understand the data you are working with and the AutoCAD commands to accurately model the surface.

Good luck!

~Lee