Allow me to repost here for depth/frequency setting +v&+8S`+
The main fresnel lens types are: cGC&O%`i,\
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* Constant groove depth. 0; OpT0
* Contant groove pitch types. Yc#o GCt
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So if your depth is fixed you will define +ve value in the cell and to specify the "height" or "depth" of each groove feature. If the frequency of the groove is fixed then you use -ve value. Say putting down - 5 this implies that there are 5 grooves with a unit length. hGF:D#jyT
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For radius, this is the curvature of the base surface. If you define one such lens and chaneg the radius and you shall see what it means. A graphic tells lounder than words. Y&k'4Y%
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For conic: check conic section using Wikipedia and you should see what conic constant means.
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