GR8 Centre-Line Tangency Further Information...

Method 1 : Building a Single Surface across a centre-line

A simple way to avoid peaks and troughs is to build a single surface for both sides of the design. If this surface is single span, then it is guaranteed to be smooth.

The only disadvantage is that the user will have to be vigilant to make sure that the surface stays symmetrical as the CVs are moved. But there is a tool that can help:

Building across the centre-line

Method 2 : Building one Half

Alternatively, if you prefer to build one half only, you will need to ensure that the centre-line CVs are maintaining tangency between the original and the mirrored half.

This can be done by aligning the first and second CVs from the edge, in one of two ways:

Building one half


The key to using all these methods is to evaluate the results. This can be done with the following tools:

For more information on evaluation, refer to the two Evaluation Theory Builders:

Implied Tangency with Rail & Square Tools

When building a Rail or Square surface along a centre-line, with the intention of mirroring to create a smooth result, use the Implied Tangent continuity option on the edge lying on the centre line.

Using the Implied Tangent option in Rail and Square surfaces

Note: Avoid using the Implied Curvature option as this tends to flatten the surface too much.