How can I build 4 dimension spline to lookup table

Question

Hello ,everyone

I want to use multi dimension(4D) spline to look up the data.

That means there are three independent value to find out one output

Are there any example or demo for that i can learn?

Thanks a lot.

Kind Regards,

Zhenhui Xu

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Martin Kieltsch · Accepted Answer

That sounds like an application for a spline_read usersub.

Depending on what element you require, you could also use a varsub, gfosub, sfosub, ....

If I was stuck to standard ADAMS elements, I'd try to evaluate several splines separately and use a solver variable to "interpolate between" these single splines.

For example you could use 2 3D splines that both use dimension #4 as the Z-axis and the variable would simply do a

func = "(AKISPL(spline_1) + AKISPL(spline_2)) / 2"

Another way to skin the cat could be to use 3 2D splines for the 3 dimensions (being all dependent on dimension #4) and "interpolate" that with an own algorithm (in the simplest form "(AKISPL(spline_1) + AKISPL(spline_2) + + AKISPL(spline_3)) / 3")