There are a wide variety of different tools available in Studio Artist for converting raster images into bezier path renditions of the image. These include techniques to generate bezier path edge sketches (like above), as well as bezier mass sketches based on cross hatching, and complete cartoon style vector renditions of of color imagery. This tip will provide an overview of different approach to generating bezier renditions of raster images.

The example above is a bezier path edge rendition made from the raster image called ‘model’ in the ‘a few source images’ folder provided with Studio Artist. The bezier paths were generated from the source image by running the Path : Generate Paths : from Source Edges menu command.

The generated paths are stored in the current layer’s bezier path frame after they are generated. The bezier path frame is a hidden buffer associated with each layer that can store and display a set of bezier paths. You can view the current layer’s bezier path frame by switching to bezier operation mode. Once in bezier operation mode you can also manually edit the individual bezier paths or hand draw new ones.

Each layer has it’s own bezier path frame. Any path menu operations that generate or modify bezier paths are doing so to the current layer’s bezier path frame. Keep in mind that if you are generating new bezier paths you probably want to initially erase the existing contents of the current layer’s bezier path frame prior to generating new bezier paths. You can either use the erase path layer command menu to do this, or shift clicking the erase button in the main operation toolbar will also do this when it resets the canvas to a default coloring.

Generate Paths

There are a large number of different Generate Paths menu options in addition to the one used above. Adjacent edges generate a bezier path on each side of an edge. Skeletons are bezier paths generated at the mid points between 2  edges, and are an attempt to represent the center spines of different image regions bounded by edges.

The NonWhite options are useful to convert a raster edge image into a set of associated bezier paths. For example, you might use some image operation or MSG preset to generate a black and white raster image edge rendition where the edges are black an the background is white. The NonWhite generate path options can then be used to convert than raster canvas image (or selection) into a set of associated bezier paths.

The Generate Paths : from Ip Op menu option is a new version 4 feature that can generate bezier paths from associated image operations.  not all image operations can generate bezier paths. If a specific image operation can generate bezier paths then this from Ip Op menu will be active when that image operation is active in the image operation editor. Image operations that support generating bezier paths include the Sketch Edge, Sketch Mass, and Color Edge.

Path Layer Commands

The Path : Path Layer Commands menus shown below provide a number of different tools that can be used to modify or enhance generated bezier edge renditions of sketches.

For example, running Size Prune , Connect if Close, and Simplify Lite menu commands on the initial bezier sketch of the model shown at the top of this tip results in the following set of bezier paths. Note how these modified bezier paths have a more stylized hand drawn appearance than the original set of bezier paths derived from the raster source image edges.

Sketch Image Operations

The Sketch Edge and Sketch Mass image operations are new to version 4 and can provide for a wide range of different sketch effects derived off of raster source images. While the normal operation of the 2 Sketch ip ops generate raster sketch images, as discussed above you can use the Path : Generate Paths : from Ip Op menu to generate a bezier path rendition of the associated Sketch effect.

The image below is a screen shot of a set of bezier paths generated using the Sketch Mass ip op and the Path : Generate Paths : from Ip Op menu command.

Once you have a set of bezier paths generated that represent a raster image, you can then paint in those paths using the paint synthesizer. This additional step allows for an infinite variety of different artistic styles to be created off of a given set of bezier paths. The bezier path images above are actual screen snaps of the canvas taken displaying the bezier paths when in Bezier operation mode. But you could generate identical raster canvas images by using a simple 1 pixel black line paint synthesizer preset.

For example, the image below shows a set of bezier paths generated using the Sketch Edge ip op displayed on top of a watercolor paint synthesizer rendition of those bezier paths.  A watercolor paint preset was initially selected and then used to paint the bezier paths by running the Path : Paint Paths : Full Layer menu command. This is an example of painting in a set of vector bezier paths with a raster paint effect into a raster canvas for raster image output.

Vector Output

The Studio Artist 4 paint synthesizer allows for vector paint effects. So you could take the initial bezier paths defining a sketch and then render them using vector paint strokes in the paint synthesizer. Or you could render them by drawing them in with raster paint effects. Vector paint strokes allows for tight anti-aliased renditions as well as resolution independent output. Raster paint strokes allows for organize paint textures, wet paint effects, smear and smudge effects, etc.

For example, the sketch image above is a vector eps sketch rendition of a raster source image of George Carlin. It was generated by first running the Path : Generate Paths:  from Source Images menu.  This generated a bezier edge sketch from the raster source image. That set of bezier paths was then painted in with the paint synthesizer by running the Path: Paint Paths : Full Layer menu command shown below.  This menu command paints in the set of bezier paths in the current layer’s bezier path frame using the current paint synthesizer settings.

For this particular example, i used a paint synthesizer preset that is capable of vector drawing and eps output of the associated vectors. Each bezier path is actually rendered as a bezier region by the paint synthesizer preset used for drawing the bezier paths, where the shape of the generated region defines a simulation of a paint or ink stroke that varies in width over the course of the path drawing. Because the final output was a vector eps file, the sketch is resolution independent and could be printed at extremely high resolutions or large print sizes if desired without losing any detail in the print.

When outputting vector artwork in Studio Artist 4 you can choose between eps, pdf, and svg vector formats. Note that in the example above the initial bezier paths have actually been converted into bezier shapes or regions that the user interprets as thick paint strokes in the final artistic rendition.

Additional Information

There are some additional tips that discuss generating and working with bezier paths and the various vector output formats.

For more information on generating EPS vector files, check out this tip.

For more information on generating and outputting SVG vector files, check out this tip.

For more information on the new Sketch image operation effects, checkout this tip.

For more information on things you can do with bezier paths in Studio Artist check out this tip.

To learn more about how to generate paint presets that do vector drawing check out this tip.

The Vectorizer is a completely different way to generate bezier region renditions of raster source images that was not discussed in this tip. For more information on the Vectorizer check out this tip.

The image below shows a simple painting generated from a single paint preset (Default:Utility:Bristle Paint-Flat”. Note the appearance is very abstract.

Now suppose you wanted to generate a painting like this that better reproduces the source image. One common approach is to work with multiple passes of the paint preset where you reduce the brush size and path length for each pass. This simulates what an artist would do in a real painting, where they would typically start with a large brush size to rough in the image and then use progressively smaller brush sizes to bring in more detail.

The image below shows off how this approach can generate additional detail. However, the painting still has a fairly abstract appearance.

Another approach to accenting edge detail in a painting is to superimpose an edge sketch on top of the abstract painting. There are a number of different ways to create this kind of effect. You could select a specific paint preset that generates an edge sketch effect. Many of these presets use path start and path end settings that focus the drawing onto the locations of edges in the source image. The example below shows off one way to add a black sketch effect to an abstract painting.

I generated a set of bezier paths from the source image edges using the ‘Path : Generate Paths : from Source Edges’ menu.

and then painted in the paths using a dark pencil preset by selecting a black pencil preset and running the ‘Path : Paint Paths : Full Layer’ menu command.

I then followed that with the Color Edge Ip Op setup to render a black edge min composited into the existing painted canvas. Note that i’m using the Source Image for the IP Source (as opposed to the current layer). This means the black edges are generated from the original source image as opposed to the painted canvas.

The 2 techniques described above work together in this example to create a nice tight edge sketch that helps the painting become more representational of the original source image. There are many different Ip Ops that can be used to create Edge renditions, including Color Edge, Edge, and Sketch as the first thing to check out. Smart Contrast, Gradient, Color Simplify, and Watershed Regionize also have parameter configurations that will generate black sketch effects. There are also many MSG presets that can create a wide range of different sketch effects.

Tightening up a Painting

A different approach to tightening up the edge rendition of a paint preset is to turn on ‘Local Image Range’ Nib Masking in the Paint Fill Apply control panel in the paint synthesizer Editor.

The various nib masking settings all work to automatically generate a on-the-fly selection mask for each individual paint nib before it is applied to the canvas. What the ‘Local Image Range’ setting does is to mask the paint nib if it spills into areas of the associated source image that are different colors the the current paint color. You can see the effect of turning on local image range nib masking below for the simple paintpreset we’ve been using in this example.

Note that the edges associated with the original source image are reproduced in the painting. However, the masking effect is very pronounced. Often a better approach is to start off by generating a more abstracted painting, and then turn on the local image range nib masking and overpaint. The example below shows off how this can give a more natural effect in the resulting painting.

There are 2 Paint Synthesizer Macroedits shown below available for you as active commands in the Help palette.

The actual specification of the size of the local image range is based on the Path End control panel ‘Local Color Range’ parameter value.

You can also use Local Color Range Path End masking to generate a tighter paint rendition. The difference between the Path End and the Nib masking approach described above is that the nib mask leads to a very tight rendition. Path End masking based on turning on Local Color Range will mask your paint paths but the complete nib will still draw, leading to a subtler, more natural paint effect, but with a subtler edge rendition due to the full paint nib being drawn.

There are some Paint Synth Macroedits available that can provide a quick way to modify a paint preset to focus on edge drawing or preserving local color areas.

Accenting Positive and Negative Space

Real painters work with their shading to help accent positive and negative space in the image they are painting. There are some different approaches you can use in Studio Artist to create this same kind of effect. One approach is to generate a region selection that breaks the image into positive and negative space, and then use that as either a selection mask for painting or as a probability modulator for things like path start and path end locations and path application probability.

The Smart Contrast Ip Op is a great tool for generating a selection mask that defines the positive and negative space in a source image. An example of what i mean is shown below.

This image was generated with the following Smart Contrast settings.

To generate a hard black and white mask image all three Smoothness controls need to be set to the same value. When they are different you will get additional gray levels in the resulting output, which can be useful if your goal is to use the output image as a probability mask in the paint synthesizer for things like path application probability based on the current selection region modulator.

To route the Smart Contrast output to the current region selection as opposed to placing it in the canvas, use the ‘Replace Region Selection’ Composite option shown below.

If you turn on Masking and then run the original ‘Bristle Paint-Flat’ paint preset located in Default:Utility used throughout this tip you will get the following kind of effect if Paint Masking is turned on.

You can turn on Masking by either checking the Mask checkbox in the main operation toolbar

or by using the ‘Canvas : Layer : Mask Status’ menu.

There are 3 different kind of masking you can use when painting. You choose them in the ‘Canvas : Layer : Paint Mask Type’ menu as shown below.

The ‘Paint’ mask type give a hard edge. The ‘Path’ mask type masks the paint paths as opposed to the paint nib, so it can be used to give a more natural appearance to a masked painting since the complete brush nib is drawn at the edge of a masked path area. Litho mask type masks the non wet part of a spreading wet preset, so it allows the selection mask to act like a lithography press where paint is applied in the non masked area by the wet spreading can move into the masked areas via drip or wiping effects.

I used ‘Path’ masking in the example below with a different preset that generates an airbrush effect. Note the smoother more natural appearance at the edges of the masked areas created by the Paint masking type.

You can invert the mask using the ‘Canvas : Selection : Invert’ menu command.

The next example was created using the same airbrush preset and the inverted selection mask with Path masking.

You aren’t restricted to dropping out the masked area in a painting as shown in the 2 examples above. The AutoPaint1 Paint Action Sequence preset located in Default : General shows off a more sophesticated way to use this kind of selection masking.

This PASeq starts off by setting the canvas to white. It then uses the Smart COntrast Ip Op as described above to generate a selection mask. The non selected area is then painted in.  Then the mask is flipped, and a paint preset with a different orientation and a luminance bias is then used to paint in the other side. So one side of the mask is painted in with darker paint that has a different orientation than the pain in the other side of the mask.

The final result for this PASeq is shown below. Note that the PASeq uses the black edge outline technique discussed earlier in this tutorial to improve the edge rendition of the painting.

So, we’ve covered a lot of ground in this tutorial tip, focusing on different approaches to improving edge rendition and representation of the source image in paintings created using the Studio Artist paint synthesizer. We’ve talked about working with different brush sizes to add detail over time to a painting, different approaches to masking, and the use of edge sketches to add additional detail rendition to painting. 

Keep in mind that you can also always mix in some of the original source image to de-abstract an abstracted painting. This could be done in a locally selective way using something like the ‘Default : Utility : Clone Source-Soft’ paint preset. Or you could use the Fixed Image Ip Op with the IP Source set to Source Image and something like a 30% Mix setting if you want to mix the source into the entire painting.