Monday, June 26, 2006

Follow-up From the User Groups

The user group meetings this month were on Site Modelling. We covered how to make a site model from a series of 3D loci, how to make a site model from a scanned image and how to modify the site model when you’ve made it. One of the questions that came up was when I’m using 2D Ploys to 3D Contours why do I recommend using 3D Loci rather than  3D Polygons. My answer was that it makes a better site model, especially when you want to add site modifiers. My friend Don came to the user group and tried out my suggestions. This is what Don said...

I have been trying out what I learnt from this NZVWUG meeting on DTM creation.

Yes you are right. I used the Site Model from Scanned Image method on a set of dummy contours I had drawn. Traced my contours. I selected "Create 3D Loci" option from "2D Poly To 3D Contours". The resulting  DTM of course didn't match the drawn contours at all well. But I could copy the appropriate 3D Loci (i.e. one which had the same Z value as the contour) and paste at reasonable  intervals along each contour. Re-run "Site Mode" and voila a much more accurate DTM.

It seems that you should give far more emphasis to the"Create 3D Loci" option in your manuals and classes. It  just gives you far more control over editing the DTM.

That revelation was worth every bit and more of the $ for Tuesday night. Thanks Jonathon.

So I guess from now on I’ll emphasise the 3D Loci more...

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