This is an advanced mesh editing function available in the toolbar, in the Mesh Edit menu or the context menu, if you right-click on a selection. It requires netfabb Studio Professional
It allows you to change the shape of objects. First, select the triangles or surfaces you want to move and activate the function Extrude Surfaces. In that mode, a grey surface is displayed which represents the new position of the extruded triangles. At the beginning it is shifted from their old position by 1mm.
You can now change the position of these triangles by drag & drop in any direction and by any distance. By pulling it outwards, the part is expanded accordingly and the volume increases. If surfaces are moved inwards, the volume is reduced. If you hold Shift, the distance by which the triangles are moved is locked and only the direction changes. If you hold Ctrl, the direction is locked and only the distance changes.
If you double-click on an existing surface of the part, the direction of the extrusion is adjusted along the orientation of the triangle you clicked on, in a right angle to its face. With every further double-click, the direction is changed by 180°. The triangle you click on does not have to be part of the surface which is extruded.
Similarly, by double-clicking on a triangle edge, the extrusion is aligned along the edge, switching the direction with every double-click.
With the button Apply in the tabsheet, the extrusion is performed. The chosen triangles are moved according to your settings and new triangles are inserted to connect the original part with the new triangles.
If the option Move Points is activated, the module does not add new triangles to expand the part, but simply moves the points of the selected triangles. That way, all neighbouring triangles are repositioned to connect the old part and the new surfaces. This can lead to a different kind of shape as the standard extrusion.
The direction of the extrusion along the three axes and the distance to the original surface can also be set in the parameters box in the tabsheet to the right. You have three fields for the direction, representing the X-, Y- and Z-axes. The proportion of the number you enter here determines the direction of the extrusion. You can enter both positive and negative values. If you want to extrude in the positive X-direction, for example, set the values for Y and Z to 0 and the value for X to any positive number. If you want the extrusion to differ from the positive X-direction to the negative X-direction by 30°, set the value for Z to 0, set a negative value for Y and set a positive value twice as high for X. If you change the position of the extrusion by drag & drop, the value are updated automatically in the tabsheet.
Shift is the distance of the new corner points of the extruded triangles to the old corner points. As for the direction, the shift can be positive or negative. Negative values make sense, for example, if you have already set the direction and want to go exactly into the opposite direction. Surfaces can be extruded at any length.
The button Estimate Direction calculates the average orientation of all selected triangles and aligns the extrusion in that direction. This is most helpful for extruding surfaces whose triangles are not parallel. The average direction of the triangles is also set automatically at the start of the feature.