Is this a known problem?

[Walter Simmons]

I’ve been working for some time, without success I might add, trying to import a table of offsets into DS. Having run out of options, and just for chuckles, I opened the file of a hull I had finished working on and exported the offsets. I quit the program, and when I restarted it, used the import table of offsets feature. You wouldn’t believe the resulting mess. The stem profile was changed to a plumb line, the transom didn’t even exist, and the sheer line took on a modified wave form.

What on Earth is going on with that? Are others importing offsets and getting at least satisfactory results? I really would like to know…

Thanks.

[Marven]

The problem with a offsets table is that the dimensions of the hull can only be presented at the intersections of ordinates and waterlines. This means that large parts of the hull are not (or badly) exported. Now in the old days this was not a problem, since the loftsman filled in the missing parts on the loftfloor judging by his experience. For a computer this is hard to do. That’s why other formats (like IGES) are used to transfer the model in such a way that every aspect is covered.

[Walter Simmons]

You’re quite right, and having built boats for 40+ years, I am well familiar with lofting by batten. I am also becoming more and more familiar with DS, and it’s really quite an astounding program. What really perplexed me, though, wass why when offsets were output by DS it was unable to recreate the same hull later on.

Obviously, there are ways around it that work just fine. I was just concerned that I was missing something basic. All in all this has been quite a transition for a builder like me who began designing using actual half models. It is proving to be well worth the time and effort, however.

Thanks.

[Author]

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