******* Editing ******* Surface editing has even fewer tools and options than its curve counterpart, but has many common points with it... So this page covers (or tries to cover) all the subjects, from the basics of surface editing to more advanced topics, like retopology. Translation, Rotation, Scale ============================ .. admonition:: Reference :class: refbox :Mode: Edit Mode :Panel: :menuselection:`Tool shelf --> Tools --> Transform` :Menu: :menuselection:`Surface --> Transform --> Grab/Move, Rotate, Scale, ...` :Hotkey: :kbd:`G`, :kbd:`R`, :kbd:`S` Once you have a selection of one or more control points, you can grab/move :kbd:`G`, rotate :kbd:`R` or scale :kbd:`S` them, like many other things in Blender, as described in the :doc:`Manipulation in 3D Space ` section. You also have in *Edit Mode* an extra option when using these basic manipulations: the :doc:`proportional editing `. Transform Panel --------------- See :ref:`modeling-curves-transform-panel`. Advanced Transform Tools ======================== .. admonition:: Reference :class: refbox :Mode: Edit Mode :Panel: :menuselection:`Tool shelf --> Tools --> Surface Tools --> Deform: Randomize` :Menu: :menuselection:`Surface --> Transform` The *To Sphere*, *Shear*, *Warp* and *Push/Pull* transform tools are described in the :doc:`Mesh Transformation ` section. Surfaces have no specific transform tools. NURBS Control Points Settings ============================= We saw in a :ref:`previous page ` that NURBS control points have a weight, which is the influence of this point on the surface. You set it either using the big *Set Weight* button in the *Curve Tools* panel (after having defined the weight in the number button to the right), or by directly typing a value in the :kbd:`W` number button of the *Transform* panel. Adding or Extruding =================== .. admonition:: Reference :class: refbox :Mode: Edit Mode :Panel: :menuselection:`Tool shelf --> Tools --> Surface tools --> Modeling: Extrude` :Menu: :menuselection:`Surface --> Extrude` :Hotkey: :kbd:`E`, :kbd:`Ctrl-LMB` Unlike meshes or curves, you cannot generally directly add new control points to a surface (with :kbd:`Ctrl-LMB` clicks), as you can only extend a surface by adding a whole U or V row at once. The only exception is when working on a NURBS surface curve, i.e. a surface with only one control point on each U or V row. In this special case, all works exactly as with :ref:`curves `. Most of the time, only extrusion is available. As usual, once the tool is activated the extrusion happens immediately and you are placed into *Grab mode*, ready to drag the new extruded surface to its destination. There are two things very important to understand: #. Surfaces are *2D* objects. So you cannot extrude anything *inside* a surface (e.g. "inner" row); it would not make any sense! #. The control "grid" *must* remain "squarish", which means that you can only extrude a whole row, not parts of rows here and there... To summarize, the *Extrude* tool will only work, when one and only one whole border row is selected, otherwise nothing happens. As for curves, you cannot create a new surface in your object out of nowhere, by just :kbd:`Ctrl-LMB` -- clicking with nothing selected. However, unlike for curves, there is no "cut" option allowing you to separate a surface into several parts, so you only can create a new surface by copying (`Duplication`_) an existing one :kbd:`Shift-D`, or adding a new one with the *Add* menu. Examples -------- Images Fig. :ref:`fig-surface-edit-select-point` to Fig. :ref:`fig-surface-edit-extruding` show a typical extrusion along the side of a surface. In Fig. :ref:`fig-surface-edit-select-point` and :ref:`fig-surface-edit-select-row`, a border row of control points were highlighted by selecting a single control point, and then using the handy row select tool :kbd:`Shift-R` to select the rest of the control points. .. list-table:: * - .. _fig-surface-edit-select-point: .. figure:: /images/modeling_surfaces_editing_selecting-point.png Selecting control point. - .. _fig-surface-edit-select-row: .. figure:: /images/modeling_surfaces_editing_selecting-row.png :kbd:`Shift-R` The edge is then extruded using :kbd:`E` as shown in Fig. :ref:`fig-surface-edit-extruding`. Notice how the mesh has bunched up next to the highlighted edge. That is because the *new* extruded surface section is bunched up there as well. .. _fig-surface-edit-extruding: .. figure:: /images/modeling_surfaces_editing_extruding.png Extruding. By moving the new section away from the area, the surface begins to "unbunch". You can continue this process of extruding or adding new surface sections until you have reached the final shape for your model. Opening or Closing a Surface ============================ .. admonition:: Reference :class: refbox :Mode: Edit Mode :Panel: :menuselection:`Tool shelf --> Tools --> Surface tools --> Curve: Toggle Cyclic` :Menu: :menuselection:`Surface --> Toggle Cyclic` :Hotkey: :kbd:`Alt-C` As in :ref:`curves `, surfaces can be closed (cyclic) or open. However, as surfaces are 2D, you can control this property independently along the U and V axes. To toggle the cyclic property of a surface along one axis, use :kbd:`Alt-C` and choose either *cyclic U* or *cyclic V* from the pop-up menu. The corresponding surface's outer edges will join together to form a "closed" surface. .. note:: Inner and Outer Surfaces have an "inner" and "outer" face, the first being black whereas the latter is correctly shaded. (There does not seem to be any "double sided" shading option for surfaces...). When you close a surface in one or two directions, you might get an entirely black object! In this case, just `Switch Direction`_ of your surface... Duplication =========== .. admonition:: Reference :class: refbox :Mode: Edit Mode :Panel: :menuselection:`Tool shelf --> Tools --> Surface tools --> Curve: Duplicate` :Menu: :menuselection:`Surface --> Duplicate` :Hotkey: :kbd:`Shift-D` Similar as with meshes and curves, this tool duplicates the selection. The copy is selected and placed in *Grab* mode, so you can move it to another place. However, with surfaces there are some selections that cannot be duplicated, in which case they will just be placed in *Grab* mode... In fact, only selections forming a *single* valid sub-grid are copyable; let us see this in practice: - You can copy a single control point. From it, you will be able to "extrude" a "surface curve" along the U axis, and then extrude this unique U row along the V axis to create a real new surface. - You can copy a single continuous part of a row (or a whole row, of course). This will give you a new *U row*, even if you selected (part of) a V row! - You can copy a single whole sub-grid. .. note:: Trying to duplicate several valid "sub-grids" (even being single points) at once will not work; you will have to do it one after the other... Deleting Elements ================= .. admonition:: Reference :class: refbox :Mode: Edit Mode :Panel: :menuselection:`Tool shelf --> Tools --> Surface tools --> Curve: Delete` :Menu: :menuselection:`Surface --> Delete...` :Hotkey: :kbd:`X`, :kbd:`Delete` The *Erase* pop-up menu of surfaces offers you two options: Selected This will delete the selected rows, *without* breaking the surface (i.e. the adjacent rows will be directly linked, joined, once the intermediary ones are deleted). The selection must abide by the following rules: - Whole rows, and only whole rows must be selected. - Only rows along the same axis must be selected (i.e. you cannot delete both U and V rows at the same time). Also remember that NURBS order cannot be higher than its number of control points in a given axis, so it might decrease when you delete some control points... Of course, when only one row remains, the surface becomes a "surface curve"; when only one point remains, there is no more visible surface; and when all points are deleted, the surface itself is deleted. All As with meshes or curves, this deletes everything in the object! Example ------- .. figure:: /images/modeling_surfaces_editing_deleting.png Before and after. In Fig. *Before and after (left)* a row of control points has been selected by initially selecting the one control point and using :kbd:`Shift-R` to select the remaining control points. Then, using the *Delete Menu* :kbd:`X`, the *selected* row of control points is erased, resulting in Fig. *Before and after (right)*. Joining or Merging Surfaces =========================== .. admonition:: Reference :class: refbox :Mode: Edit Mode :Menu: :menuselection:`Surface --> Make Segment` :Hotkey: :kbd:`F` Just like :ref:`curves `, merging two surfaces requires that a single edge, a border row of control points, from two separate surfaces is selected. This means that the surfaces must be part of the same object. For example, you cannot join two surfaces while in *Object Mode* -- but you can of course, as with any objects of the same type, join two or more *Surface* objects into one object :kbd:`Ctrl-J` -- they just will not be "linked" or merged in a single one... Yes, it's a bit confusing! This tool is equivalent to creating edges or faces for meshes (hence its shortcut), and so it only works in *Edit Mode*. The selection must contain only border rows of the same resolution (with the same number of control points), else Blender will try to do its best to guess what to merge with what, or the merge will fail (either silently, or stating that ``Resolution does not match`` if rows with different number of points are selected, or that there is ``Too few selections to merge`` if you only selected points in one surface...). To select control points of different surfaces, in the same object, you must use either border select or circle select. Holding down :kbd:`Ctrl` while :kbd:`LMB` will not work. So to avoid problems, you should always only select border rows with the same number of points... Note that you can join a border U row of one surface with a border V row of another one, Blender will automatically "invert" the axis of one surface for them to match correctly. NURBS surface curves are often used to create objects like hulls, as they define cross sections all along the object, and you just have to "skin" them as described above to get a nice, smooth and harmonious shape. Examples -------- Fig. :ref:`fig-surface-edit-join-ready` is an example of two NURBS surface curves, **not** NURBS curves, in *Edit Mode*, ready to be joined. Fig. :ref:`fig-surface-edit-join-complete` is the result of joining the two curves. .. list-table:: * - .. _fig-surface-edit-join-ready: .. figure:: /images/modeling_surfaces_editing_joining-ready.png Joining ready. - .. _fig-surface-edit-join-complete: .. figure:: /images/modeling_surfaces_editing_joining-complete.png Joining complete. Subdivision =========== .. admonition:: Reference :class: refbox :Mode: Edit Mode :Panel: :menuselection:`Tool shelf --> Tools --> Surface tools --> Modeling: Subdivide` :Menu: :menuselection:`Surface --> Segments --> Subdivide`, :menuselection:`Specials --> Subdivide` Surface subdivision is most simple: using either the *Subdivide* entry in the *Specials* menu :kbd:`W`, or the *Subdivide* button of the *Curve Tools1* panel, you will subdivide once all *completely* selected grids by subdividing each "quad" into four smaller ones. If you apply it to a 1D surface (a "surface curve"), this tool works exactly as with :ref:`curves `. Spin ==== .. admonition:: Reference :class: refbox :Mode: Edit Mode :Panel: :menuselection:`Tool shelf --> Tools --> Surface tools --> Modeling: Spin` :Menu: :menuselection:`Surface --> Spin` This tool is a bit similar to its :doc:`mesh counterpart ` but with less control and options (in fact, there is none!). It only works on selected "surfaces" made of *one U row* (and not with one V row), so-called "surface curves", by "extruding" this "cross section" in a square pattern, automatically adjusting the weights of control points to get a perfect circular extrusion (this also implies closing the surface along the V axis), following exactly the same principle as for the *NURBS Tube* or *NURBS Donut* primitives. Switch Direction ================ .. admonition:: Reference :class: refbox :Mode: Edit Mode :Panel: :menuselection:`Tool shelf --> Tools --> Surface tools --> Curve: Switch Direction` :Menu: :menuselection:`Surface --> Segments --> Switch Direction`, :menuselection:`Specials --> Switch Direction` This tool will "reverse" the direction of any curve with at least one selected element (i.e. the start point will become the end one, and *vice versa*). Mainly useful when using a curve as path, or the bevel and taper options... Other Specials Options ====================== .. admonition:: Reference :class: refbox :Mode: Edit Mode :Menu: Specials :Hotkey: :kbd:`W` The *Specials* menu contains exactly the same additional options as for curves, except for *Set Radius* and *Smooth Radius*. Conversion ---------- As there are only NURBS surfaces, there is no "internal" conversion here. However, there is an "external" conversion available, from surface to mesh, that only works in *Object Mode*. It transforms a *Surface* object into a *Mesh* one, using the surface resolutions in both directions to create faces, edges and vertices. Misc Editing ------------ You have some of the same options as with meshes, or in *Object Mode*. You can :ref:`separate ` a given surface :kbd:`P`, make other selected objects :ref:`children ` of one or three control points :kbd:`Ctrl-P`, or :doc:`add hooks ` to control some points with other objects. The *Mirror* tool is also available, behaving exactly as with :doc:`mesh objects `.