Zooming In on a 3d Surface

Applies to: 3D and Studio. New in TableCurve 9.

To examine part of a surface closely, you need to tell the program which part -- and a surface gives you no good way to say it. A rectangle drawn on a rotated surface is not a rectangle in x and y, so dragging a box on the surface itself cannot mean what you want it to mean. The alternative, typing four range numbers into a scaling dialog and looking at what you get, is accurate and slow.

TableCurve 9 gives you a third way: it lays the surface flat for a moment so you can point at the region you want.

How to Do It

· Right-click the surface and choose Enter Zoom Mode.

· The pane changes to a contour map of the same surface, seen from directly above and in the same colours. Every peak and valley is where it was; only the viewpoint has changed.

· Drag a box around the region you want.

· The surface returns by itself, scaled to the box you drew.

There is nothing to confirm and no dialog to close. The contour is not a view you have switched to -- it is there to be aimed at, and it leaves as soon as it has been.

If You Change Your Mind

· Cancel Contour (right-click, while the contour is showing) -- returns the surface exactly as it was, with no zoom taken.

· Restore Scaling - Undo Zoom (right-click the surface) -- undoes a zoom you have already taken and returns the surface to automatic scaling. This item appears only when there is a zoom to undo.

Aiming at Something Very Small

If the region you want is too small to box accurately, zoom the contour first with the mouse wheel and then draw the box. Wheel zooming does not end the gesture -- only drawing a box does -- so you can magnify the contour as far as you need to before committing.

The Contour Keeps the Surface's Colours

The contour is drawn in the same colormap as the surface you right-clicked. A surface rendered in Parula is aimed in Parula; a shaded surface is aimed in the matching single-colour ramp. This is deliberate: the contour is the same surface seen from above, and it would be a poorer aiming device if it arrived in unfamiliar colours.

Your own contour settings are not affected. The colormap is borrowed for the gesture and given back when the surface returns.

When Enter Zoom Mode Is Not Offered

The item appears on surfaces drawn as a gradient or as a shaded surface. It is not offered on:

· Wire frame and mesh plots, which have no colormap to lend -- a colourless contour would be harder to aim with than the surface itself.

· Panes already drawn as a 2D contour, which need no help: drag a box on them directly.

What the Zoom Sets

The box sets the x and y ranges, exactly as though you had entered them in the 3D scaling dialog. The z axis is rescaled automatically to the region you zoomed into, so a shallow feature that was invisible against the full height of the surface fills the frame once you are inside it. That is usually the reason for zooming in the first place; if you need the original z range kept, set it explicitly in the scaling dialog after the zoom.