Archive for May, 2010

May 27, 2010

Drawing in Perspective using Adobe Illustrator

For all of you who have endeavored to draw street scenes in Illustrator, there’s good news. Adobe Illustrator makes it a breeze to draw in perspective. All it needs is to become familiar with the underlying concepts and the tools provided and you are ready to go. Here’s a quick synopsis of the tools and concepts. For detailed understanding there’s a full tutorial in downloadable PDF file explaining how a drawing of Taj Mahal was drawn in Illustrator.

Taj.jpg

Let’s start with the basic concepts:

But before we begin, please understand that Perspective Drawing in Adobe Illustrator is NOT a 3-D environment. It is an extension of traditional perspective drawing techniques. Artists have the capability to define a perspective grid (one-point, two-point or three point), define a relative scale, move the grid planes, and draw objects directly in perspective.  Or  they can attach flat art onto the grids by dragging with the new Perspective Selection tool. There are several operations such as Transform Again that honor Perspective and therefore enable quick drawing in perspective.

Let’s see how one can draw using perspective. The first step is to set up the Perspective Grid. You can render a Perspective Grid via View>Perspective Grid menu or just by selecting the new Perspective Grid (PG) tool (or using the shortcut Cmd/Ctrl + Shift + I to show/hide Perspective Grid).

The Perspective Grid tool in the toolbar is used for fine-tuning this grid though widgets provided on the grid. The Grid Plane widgets allow three state behaviors using Opt/Alt click:

(a) Grid plane
(b) Transparent fill plane, and
(c) No plane view state.

PS_tool.png

The Perspective Selection Tool

Widget_PG.png

The Plane Selection Widget

Perspective rulers are available and can be turned on or off from View>Perspective Grid>Show Rulers. These rulers display along with the Perspective Grid. You can draw in Perspective using line group tools and rectangle group tools while the grid is visible. The Perspective Selection (PS) tool (available in the same tool group as PG Tool) allows a perspective object to be moved, scaled, duplicated and transformed in perspective–and placing regular objects into perspective (using ‘1’, ‘2’ or ‘3’ keys to select the desired plane while dragging). It is also possible to move/duplicate objects from one plane to the other using PS tool. Grid opacity can be controlled in the Perspective Grid Presets. ‘View->Perspective Grid->Snap To Grid‘ enables snapping to Grid. Scale can be defined–to be used in displaying readouts to give the real world dimensions of an object (honoring the scale of grid). While Perspective Grid is visible you can easily switch to Perspective Selection Tool using Cmd/Ctrl from rectangle/line group tools and the PS Tool. Text and Symbols can be placed in Perspective, text being editable using the button given in the Control Panel. Placing objects on perspective grid plane works for most objects except raster images. Pattern-fills will not honor perspective.

You can also do:

(a) Perpendicular Movement of Perspective Objects (enabling move/duplication of objects such that the move happens towards a plane parallel to it). Pressing ‘5’ key on the keyboard’s top row of keys before or during the movement using PS Tool would enable regular Perspective movement into Perpendicular Movement of Object.
(b) Marquee selection (You can select between normal marquee and Perspective marquee after starting to drag the PS tool and then switch between different plane of current grid using ‘1’, ‘2’, ‘3’ or ‘4’ keys),
(c) Real-world measurements in Control Panel and
(d) Arrow keys movement in Perspective for Perspective Objects.

You can switch the active plane by clicking on the cube’s planes in the on-screen widget while having ‘Perspective Selection‘ or ‘Perspective Grid‘ tools selected and also have a ‘No Plane‘ active state. A context/object menu is available to attach an object to the currently active plane in Perspective. Similarly a Perspective Object can be released from Perspective using the ‘Release with Perspective‘ item in Context/Object menu, without affecting the appearance of the object.

Objects are aware of the height/depth at which they belong in perspective. This means that by doing a Perpendicular movement of object the dimensions reported in Info/Control panel will remain true. The Perspective Selection tool works in object’s plane i.e. Scale/Move takes place in plane where the object belongs and not in current plane height/distance. Multiple bounding boxes are shown in case objects selected are at different heights (even if they are in the same plane). Move operation (with PS tool) would work fine for multiple selections, i.e. each object would move in its own plane and the relative positioning would be maintained. Transform Again (Cmd/Ctrl+D) works for Perpendicular Movement. Scale would scale the objects whose bounding box is used for scaling even when multiple objects are selected.

Before drawing/placing object you can infer plane positioning from (Smart Guides have to be ON for this):

a. Other objects by going to one of the anchor point (getting the ‘anchor’ label) and pressing Shift key. This would temporarily hide other planes.
b. Grid Lines by going to ‘Intersect’ point and again pressing Shift key. Changing plane in this state would bring that plane to appropriate offset.

Once the object is drawn/placed the inference mode would be reset and all planes would get restored to normal visibility/offset. A plane can be moved to match an object’s depth/height. To do this select the object and then use ‘Object->Perspective->Show Object Grid Plane‘. ‘Opt/Alt+Drag’ a plane would make a copy of the object
on the plane to new location. If nothing is selected on plane all objects would be copied else only the selected once would be copied. For precise Perpendicular movement any plane can be moved to any specified depth by doing a ‘Shift+Click’ on plane widget. The dialog would have options to move/copy objects along with the plane. This would come only with Perspective Selection tool and not the grid tool. When multiple objects across the plane are selected the info/control panel won’t show any information. Moving a plane with Shift key pressed would snap the plane to the next available grid line. There’s a Plane Switching widget available that activates whenever Perspective Grid is visible. It works with all the Perspective aware tools and can be used to switch planes. View->Perspective Grid -> Define Grid functionality allow to numerically manipulate the currently defined grid in the document and also one can save the grid as a Preset from the same dialog.

Double-clicking on the  on Perspective Selection tool opens a dialog that provides fine control over the various parameters for this tool.

Here’s a step-by-step guide explaining how the Taj was created (best downloaded and viewed in Adobe Acrobat):

Taj_Perspective.pdf

The Taj drawing file:

Taj_Perspective_Drawing.ai

Contributed by Anil Ahuja, Adobe Illustrator Engineering Team

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May 20, 2010

Ruler updates in Illustrator CS5

Based on PostScript model, Illustrator’s artboard position was defined in the first quadrant. This means that the rulers originated from the bottom left of the artboard. In Illustrator CS4, we introduced multiple artboards, but ruler-origin remained the same – at bottom left of the first artboard.

Old_Rulers.gif

In Illustrator CS5, there has been a significant functional update in ruler. Illustrator CS5 now has a new kind of rulers, called the Artboard Rulers. The origin of these new rulers are at the top-left of ‘each‘ artboard. Which means that each artboard can have its own custom ruler-origin.

New_Rulers_CS5.gif

ArtboardRulers_CS5.gif

If usage of rulers is common in your design process in Illustrator, here are a few things of interest in AiCS5:

  • With this update positive vertical increment happen in the Y-axis when going from top to bottom, similar to other applications like InDesign and Photoshop.
  • When changing the ruler origin, pattern fills used to get re-tiled and their appearance changed. With Artboard Rulers, ruler-origin changes do not affect pattern fills.
  • For those using scripts, the existing scripts from older versions would continue to work the same way. They need not be modified to updated coordinates.

Here a great video on Adobe TV by Mordy Golding that explains this.

Contributed by Neeraj Nandkeolyar, Illustrator Workflow Team

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