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Edit Operator - Inspecting and Fixing

This chapter covers mainly the process of inspecting and fixing a model on which Make Polygons is failing. This happens because there are strong constraints on polygons, and it may be hard to know when something is wrong at a first glance. We will also cover other situations in which your model may look broken or un-editable, trying to give you some way to exit from this bad situations.

Corners

Fig. 1 Corners on the edges which are attached to the same vertex. The Editing normal is used to determine which edges make a corner.

A Corner is a connection between two edges attached to the same vertex. On each edge, not all possible edges couples will be used to generate a corner: the Editing Normal on the vertex is used as a reference to give the edges an order; after ordering the edges, a corner will be generated only between two consecutive edges. If the angle between two edges is greater than 180°, the corner will be skipped. If the angle is approximately 180°, a special corner will be generated which can be used only to generate polygons having sides with more than one edge (a corner with approximately 180° can't become a polygon corner, but it can still be used to generate the borders of the polygon)

You can see the corners on each vertex by activating the Show Corners option. The corners are candidate to become corners for a polygon generated with Make Polygons; corners exist before polygons, so you need correct corners to make a correct polygon. If you think the corners has not been computed correctly, you may have some problem either with the handles (edges) or with the Editing Normals. We will see now two separated situations and how to fix things.

Fixing Corners on a Smooth Vertex

On smooth vertices things are a bit more easy,because of the constraints between the handles and the editing normals. If you think a corner is wrong, you must check all your handles directions around that corner. You can do this by either accessing the Change Handles in the Edit Operator or switching to the Pointings Operator (Change Handles is a simplified version of the Pointings Operator with no menus). What you have to do is to point the handles (one by one) and change the Roll, the yellow arrow.

Fig. 2 Fixing Handles on a Smooth Vertex to change the corners. Here you need to drag the yellow arrow (the Roll) to recompute corners.

Fixing Corners on a Sharp Vertex

On sharp vertices things are more complex. Depending on the direction of your handles, actions like Fix Normals may compute an editing normal on the vertex which is not what you wish to have. Since handles can go in any direction there is not a unique way to assign a normal which make sense on a vertex. And there is not a unique configuration of corners which make sense. So, if you don't like the way corners as been generated you can change it by changing the editing normal. To do so, you need to enter Change Handles in the Edit Operator (in Pointings Operator can't be changed freely, so here you have only one option). You need to point a vertex first, then you need to drag the little sphere on top of the Editing Normal with your mouse: you will, eventually, see a complete reconfiguration of your corners around the normal. Technically speaking (if you can understand this): Curved Poly will recompute corners by ordering first the edges on the plane orthogonal to the normal; changing the normal will change the plane and therefore the edges order.

Fig. 3 Fixing the Editing Normal on a Sharp Vertex to change the corners.

Edge Bindings and Polygons Matches

Edge bindings are connections between corners, computed through edges. You can see edge bindings by activating the Bindings option, but you have to activate the Corners option first. They are drawn as blue curves.

Fig. 4 An Edge Binding on a single Edge on the left. An Edge binding through more edges on the right.

An edge binding can be made of one edge, if the edge starts and end with acute corners. When an edge has a corner with and angle of almost 180°, the binding will step to the other edge putting more edges together.

Fig. 5 4 Bindings and the Perfect Match for a Curved Quad.

When, starting from a corner and following the bindings, Curved Poly can get back to the starting corner, we have a closed loop of corners connected by bindings which becomes a Polygon Match. These matches are used to generate polygons, and this is the reason why you need to correct corners every time you find vertices which can't generate polygons.

Fig. 6 A More Complex Example, showing a net of edges without polygons but with a perfect set of Edge Bindings and Polygons Matches. One click on Make Polygons will generate all the polygons at once.

Selection Inspector

You can activate the Selection Inspector to inspect any selected element in you model. The inspector shows:

Vertices: the list of selected vertices. Each vertex is numbered.You can activate Vertices Edges, Vertices Polygons and Vertices Corners to have the sublist of (respectively) edges, polygons and corners attached to each vertex.
Edges: the list of selected edges. Each edges is numbered. Between square brackets, you will find the indices of the vertices at the extremes of each edge. You can activate Edges Polygons and Edges Corners to have the sublist of (respectively) polygons and corners attached to each edge. (Remember that an edge can have a maximum of two polygons, here called the Front Polygon and the Back Polygon, and a maximum of 4 corners)
Polygons: the list of selected polygons. Each polygon is numbered. Between square brackets, you will find the indices of the vertices at the corners of the polygons.

Inspecting selected contents may help you understand in depth serious issues in the relationships between your elements. For example you may find that you attached an edge to the wrong vertex, or you may find a polygon is connecting vertices that you didn't want to connect because of a bad disposition of corners.

Other Fixes which can help you

Here a few more fixes not related to Make Polygons which can help you exit from some rare bad situations. With my best wishes that you never fall in them.

Broken Edges

When you use unwrapped surfaces it may happen that something goes wrong in the relationships between edges and unwraps, compromising the structure of runtime curved polys. If you see one or more edges change their vertices for no reason, it may be because of this. What you should do is to move to Geometry Operator and Reset Geometries. Then, go to the Unwraps Operator, select everything and press on Empty Unwrap. This will reset all unwrap groups, potentially removing the issue. You should always execute Edit Operations first and separate geometries and compute unwraps at a second time.

Lost Editor Asset

You may have lost your editor asset if you haven't followed the tips in chapter Assets and Libraries: you can still recover your model. Do this:

import your model in a new Curved Poly.
Go to Geometries Operator and Clean Geometries.
Go to Unwraps Operator and Remove Unwraps with Empty Unwrap.
Go to the Edit Operator, select All and press Remove Doubles. The default distance should be enough to remove duplicated vertices which may happen after a re-import of a runtime model.
Save or Save as new. Now you will have a copy of your shape with its own editor asset. You will have to re-unwrap the shape if it had uv coordinates.

Messed Polygons

Select all polygons.
Cancel Polygons.
Make Polygons.
You can try also: Double Click on Flip Polygons (this will force a few controls on polygons and normals which may help)

Frozen Interface or Operator

If your interface is not answering, it may be your model is in a broken state which makes something fail so badly that curved poly can't even draw or activate the user interface correctly. Because of this you may miss some important controls in the Scene View, making impossible for you to execute some actions. If this is the case you can try:

UNDO: sometimes and undo can make miracles. Sometimes you need more than one undo.
Don't Save in the inspector, Create a new Curved Poly and Import the previous model.: this will reload in a fresh Curved Poly the last Saved Edit Version of your model.
Save in the inspector, Create a new Curved Poly and re Import: this may help recover the content of your model.