Topic: Join of Bezier curves (finding of test points)

Hello, the help in cubic Bezier curve recovery is necessary. A problem essence: initially there was one Bezier curve which has been divided on two parts in the certain relation. Now it is necessary on the basis of available two curves, to recover initial, that is to find test points of an initial curve, initial and finite for us is available. I found at this forum a solution of a problem (https://rsdn.org/forum/alg/2712918.all the Author: McSeem2 Date: 31.10.07 a subject, and here the comment with the decision https://rsdn.org/forum/alg/2714553.1 the Author: McSeem2 Date: 01.11.07), but faced errors at calculations. To comments it is written:" To us points 1, 12, 123, 1234, 234, 34, 4 are known. It is necessary to find points 2 and 3. They always are on the straight lines set by points 1-12 and 4-34 accordingly. Thus the distance 1-12 corresponds with 12-2 the same as 123-1234 with 1234-234. Any incorporated curve is calculated at any deal. Further, on the calculated curve we check an error on set of simple criteria - it is again divisible turned out curve at t=d1 / (d1+d2) and we look at distance from the calculated test points to the initial. "I do not understand that such d1, d2 and why the formula looks so, with remaining understood. The task entirely looks so: to divide a Bezier curve on two in the certain relation. Then on the basis of two received curves to recover an initial curve and to define, in what relation it has been divided. Thanks for the help