Convert to TIN

Applicability:

• Cadcorp SIS Map Modeller
• Cadcorp SIS ActiveX Modeller

Ribbon Group:

Edit-TINs

Map Window:

Conditions for use:

• Item Class: Grid
• Minimum number selected: 1
• Minimum item status: Editable

Associated commands:

• Drape Geometry
• Perimeter
• Merge
• Subdivide
• Snip

Description:

 Convert to TIN converts a Grid item into a TIN item.

A Grid item models a 3D surface with regularly spaced heights. This is wasteful in flat areas, such as the sea in coastal areas. When SIS converts a Grid into a TIN it tries to use as few triangles as possible, since this saves memory and makes the TIN draw faster.

Therefore SIS tries to use a large triangle to cover lots of Grid item points, this will result in perfect accuracy at the triangle corners, but deviations in the triangle's interior. If the deviation is larger than a tolerance then SIS will split the triangle up into smaller triangles. You can specify this tolerance in any linear unit and SIS will convert it to metres. The smaller the tolerance you choose, the more triangles you will get.

TIN items usually draw quicker in 3D than Grid items. Also, some 3D formats do not support Grid items, so by converting the Grid items before exporting you can choose the tolerance:

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