ATM Plop Mirror cell optimisation

["A&S Hincks" <hincks@bigpond.net.au>]

Hello All,

I am curious to know whether anyone has tried optimising their mirror cells
with Plop and have experimented with the number of mesh rings (ie. holding
all other parameters constant while varying the n-mesh parameter.

Intuitively I expected the support radii to tend to a certain value as I
increased the number of mesh rings (and hence the number of triangles in the
mesh). The results of the analysis surprised me a little in that the support
radii jumped around quite a bit and I could not accurately guess what the
optimal support placements should be (refer below table).

Does anyone know why this is occuring and how I can achieve a consistent
result? Bear in mind that as an accountant I make a pretty lousy physicist
and to be honest I'm pretty out of my depth with Plop.

For example, for a 406.4 mirror, thickness 35, focal length 1816.1, 27pt
cell, Plop returned the following:

n-mesh rings                                support radii result
-------------     ----------------------------------------------------------
----
                        r0                r1                r2
r3                r4
20                    0.335003     0.801178   0.758508     0.544883
0.757141
21                    0.329036     0.805115   0.761347     0.572158
0.732459
22                    0.326226     0.795174   0.747227     0.587329
0.741564
23                    0.331383     0.79782     0.751002     0.563569
0.75082
24                    0.333038     0.801324   0.756377     0.549389
0.756557
25                    0.329045     0.795616   0.747016     0.572922
0.744651
26                    0.330836     0.794706   0.747609     0.569415
0.747278
27                    0.331978     0.797954   0.752574     0.557907
0.75234
28                    0.32849       0.801079   0.757649     0.573552
0.735349
29                    0.328992     0.793848   0.746566     0.578346
0.741768
30                    0.330373     0.797144   0.75073       0.56611
0.746713
31                    0.327846     0.798024   0.754994     0.579976
0.731655
32                    0.328083     0.798331   0.755016     0.58111
0.732433
33                    0.32912       0.794711   0.747819     0.574986
0.742759
34                    0.32706       0.795844   0.748759     0.579121
0.74381
35                    0.330804     0.799471   0.756148     0.569605
0.734306
36                    0.328309     0.798031   0.754552     0.577187
0.735413
37                    0.329682     0.800543   0.757934     0.565654
0.74106
38                    0.32996       0.795729   0.749041     0.570126
0.746177
39                    0.331176     0.798487   0.752948     0.55984
0.750095
40                    0.328836     0.800043   0.756591     0.57073
0.738209
41                    0.329205     0.793101   0.746688     0.576195
0.743596

Cheers

Andrew Hincks