ZModeler2 Lesson#2: "Modify..." tools

"Modify..." tools in commands bar

This is a brach of the most recently used tools - they are modification tools. While modelling, certain polygons or vertices might lay improperly and you will always need to improve the mesh, refine some edges, delete unused details and such. Most of these modelling steps are performed with modification tools.

You have learned so far a pair of modification tools. They are Move and Rotate. In certain 3D sotware packages these tools are used so often that they have their own buttons in toolbar. In ZModeler I prefer assigning hotkeys to pick the tool, instead of placing them in toolbar - so, if you find certain tool commonly used, you can assign desired hotkey to this tool. Hotkeys assignment will be exaplained in advanced lessons.

This tool allows to attach geometry of one object to a geometry of another object (or simply "merge" them together). Depending on options selected in advanced settings box, this tool can delete source object or use it's copy; it can attach object with all it's children or without them. Additionally, this tool allows to attach multiple objects at a time.

To perform attaching, switch to objects level, highlight and click on "source" object (Cylinder) and then highlight "target" object (Cone). An arrow will be drawn that "source" is about to attach to "target".

When you click on target node, source will be attached. The right image shows that cylinder is not longer a separate object - it's geometry is now an integral unity with Cone object.
To attach multiple objects at a time, click on "Attach Multiple" button in options box. A dialog box will popup. First of all, click on "Change..." button next to "Attach to:" field. Another dialog box will popup and list all mesh objects in scene (see an image on the left). Select target object in this list and click OK. You will return to first dialog, but this time it contains selected object name in "Attach to:" fields and lists all other objects, so you can select several objects to attach (see an image on the right).

You can not attach an object to itself or to it's direct or indirect child object. Using an image on the right as an example, this would mean the following: Box1 can't be attached to Box2 or Box3; Box2 can't be attached to Box3, but can be attached to Box1. Box3 in a run can be attached to any of objects.

This tool can be applied to vertices and pefroms vertices break-up. If adjacent polygons share the vertex, then this tool will create one vertex for each polygon - this can be used when you need some shading tuning, painting or texturing, or when you are about to add some details in the point of break-up. The image on the right shows the result of breaking one vertex. After breaking a vertex - new vertices have been moved away to show what exactly has happened after breaking up.

With this tool you can connect two group of vertices, bridging them with a strip of polygons. The image on the right shows an example of a mesh - it's split onto two pieces, and these pieces can be connected together by creating a strip of polygons with Create\Polygon\Strip. On the other hand, if you want to speed this up, Connect tool will do it for you. All you need is to select boundary vertices on each "side" of connecting pieces. Image below shows which vertices are selected - I've painted with red color two chains of vertices, so you can see what exactly have been selected.

Once you've selected a pair of chains of vertices, select the tool and click in view to apply it (you don't need to switch to selected mode). A bridge of connecting polygons will appear. Image below shows a result of applying Connect tool. I've switched to polygons level and selected newly-created triangles, so you can see what exactly have been done by Connect tool:

The most self-explaining tool - deletes whatever you click on. Additional settings box of this tool contains switch option Children and defines behaviour of children nodes of the object you are deleting. This can be set to either Delete (children nodes will be deleted) or Relink (children nodes will relink to the parent of the node you are deleting). This is a widely used tool and Del is a hotkey for it.

Exact Transform
This tool performs Exact transformation of node's local axes or it's geometry. Exact transformation allows to type offset, rotation and scale values and apply these transformations. Tool can be applied to only one object at a time and when applying, a dialog box will appear. In this dialog you specify whether you are going to modify local axes orientation (geometry will be affected) or only node's geometry should be modified. If you are going to modify geometry, check "Transform Geometry" box first. Then enable or disable desired rows of modifications: offset, rotation and scale and finally type transformation values.

Free Form Deformation will be described in advanced lessons.

Flip tool embeds several multy-purpose tools, depending on what level you apply this tool on. On vertices level this tool flips normal vectors. If mesh object has normals flipped to the other side (inside an object), this operation can fix it.

When applied on Polygons or Objects level, this tool flips visible side of polygons (by default only one side of polygon is visible). You can flip individual polygons or a whole object. This is required when object is flipped outside in - usually after Mirroring an object. When flipping on objects level, normals are flipped too. So, before flipping, consider which flip you need: normals (user vertices level), polygons (use polygons level) or both (use objects level).

Finally, this tool hides one commonly used operation called edge turning. When applied on edges level, this tool turns an edge. Image on the right shows an example.

Edge can be flipped (turned) only when it belongs to two triangles and these triangles with this "shared edge" forms a quad. Like on the image, when highlighting an edge: two triangles are highlighted - this is the only case when flip is possible. Also note, that you can flip only one edge at a time.

This is an insertion tool. It inserts vertex into edge or polygon. After inserting a vertex an according edge is divided, or, when inserting to a polygon, it's split to smaller triangles. Inserting of vertices used mostly when you need to refine geometry, add some details. Instead of deleting and then re-modelling certain areas of the mesh, you can insert some vertices. It's worth noticing that newly vertices lay exatly on surface, and in most of cases vertices do not even need to be moved after insertion. The first image on the right shows result of inserting a vertex into an edge. Vertex was inserted under cursor and adjacent quads have been converted to triangles. The second image is an insertion of vertex on polygons level.

The power of this tool comes up on Edges level with combination of Flip tool. Using these tools, you can turn a pair of triangles into four triangles by cutting them. This requires applying "Insert" tool on opposide edges and "Flip" tool on diagonal edge. Animation on the right is an illustration.

This is a case where usage of hotkeys really improves your work. By default, "Ins" key assigned to Insert tool (it performs insertion and does not select the tool for you), "F" key assigned to Flip tool. So, in this anitmaion, a button flashing in the bottom shows when I pressed hotkeys for "Insert" and "Flip" tools. Increasing detail this way is a very fast and straightward way.

Mirror tool allows to mirror mesh geometry or some parts of it. The first word about this tool is that it depends on axes mode you have selected in main toolbar. Each time before applying this tool, check which axis is selected. As you might guess, applying this tool in "Screen XY" mode will flip object vertically and horizontally at a time. So, "Screen X" OR "Screen Y" would be you most commonly used choice for this tool. An additional options box contains the following options: All these options (except "Base to pivot") affects only on Objects level. Image on the right shows an example of applying Mirror tool to selected vertices (I've highlighted these vertices with blue glow on the image). "Screen X" axes mode was toggled on and options which were set on and off are also shown on the image.

It's recommended to avoid mirroring local axes (matrix) with this tool, since there is a very important "axes relative directions". This is a direction of "Z" axis when viewing from "Y" arrow beam to other axes: if an "X" beam points to the right, then "Z" will point upward (but not downward). Even if you rotate local axes, this "relative direction" will always stay unchanged. Since mirror tool can change this relative direction of axes, use "Mirror Matrix" option only when you exactly need it.

Move, Rotate and Scale
These tools have been described already on Basic Editing page.

The following group of tools, under a Submesh... branch performs operations on mesh sublevel only. They are, in general, a "deep mesh editing" tools, unlike the rest of "general purpose" modify tools described above.

Cleanup of mesh means removing isolated (unused) vertices and invalid polygons. Such a vertices and polygons might be a result of mesh optimization or when mesh was loaded from file and already contains elements that could be cleaned up. Most of ZModeler tools perforums clenaup transparently (so you don't need to perform mesh cleaning at all), but in certain cases some tools can leave elements. For example, when you create a polygons with any of Create\Polygon tool, you can place new vertices with mouse cursor and can interrut tool before polygon was created. In such a case an unused vertex will remain in the mesh. You can used Cleanup tool on a final well-modelled mesh before exporting, texturing or adjusting shading.

Detach tool is an opposide to Attach tool. This tool detaches polygons into new object (optionally). You can model a single mesh object for simplicity and detach certain parts to separate objects (e.g. you can create car's body as whole and then detach glasses, doors, hood etc.)

An "inplace detach" means that group of polygons will be detached from the rest of the mesh - they will use their own vertices and will not share them with other polygons. This is called to be separated. Inplace detach is widely used before texturing and shading tuning. This will be described in advanced lessons.

Extrusion is a powerful modelling tool which creates a geometry basing on existen mesh edges vertices or polygons. The best way to add a row of polygons on mesh boundary is to extrude desired edges. Creating an inset or offset gaps in mesh with extrude tool is also well done. In most of cases, this tool is applied in selected mode. Since this tool internally uses Modify\Move tool, it depends on axes modes, so check what axes mode is toggled before applying.

Vertices (or Edges) extursion goes the following way: select desired vertices, switch to selected mode, check which axes mode is toggled on and then drag vertices aside. You will see a row of new polygons created:

Polygons extursion is very likely - selected polygons are pushed or pulled, depending on axes mode you have chosen. Image below shows an extrusion of two selected triangles in "World-Y" axis:

Additional settings box for this tool contains the following options:
  • Quad sides or Triange sides switch - defines which polygon type will be used for newly-created polygons.
  • Shape edges - is a shading-specific option. It will be discussed in advanced lessons.


    This tool is used solely for shading purpose and will be discussed in advanced lessons chapter.

    Consider, you have a breaked vertices in mesh and would like to merge them into one vertex. Image on the right shows three pairs of sliced vertices in a line and fourth pair is welded. One of such a pairs is highlighted. Weld tool can merge this pair of vertices into single vertex. To perform welding, this pair should be selected and then Weld tool should be applied. Note, that you do not need to switch Selected Mode On to weld group of selected vertices - weld tool will consider that you are welding selected vertices in any case. By default, "W" key is assigned for welding tool (it will apply tool). So, selecting neighbour vertices and pressing "W" key will result in welding, like on the image below:

    Another way of using this tool is a Multiple-target mode. If you have a dozen of "pairs" of vertices you would like to weld, and they are very close to each others (on the image above, there are two pairs of such a vertices in a row), "multiple-target" weld is your choice. In this mode, Weld tool will find an isolated groups of vertices among selected vertices in mesh and weld these groups separately. When additional settings box is expanded, you can check a Multy-target mode option and adjust precision values. Precision values control the spread of vertices in each group (position of vertices, direction of their normals and their UV-mapping affects). In the example above, I would like to merge two left pairs of vertices. Precision (maximum distance between vertices in one group) have been set to 0.1, Smooth (maximum angle in degreese between normals) have been set to 180 (this is the maximum possible value, so normals do not affect vertices group detection), UV-Limit (vertices texture coordinates precision) have been set to 1.0 (default value - this is pretty high value so texture coordinates almost have no effect). Then I selected these vertices and applied the tool. Result is on the image below: