Autodesk on Friday released a major update to SketchBook Pro software that has artists switching from pencils and paints to virtual canvasses on iPhones or iPad tablet computers.

SketchBook Pro software upgrades were crafted to take advantage of improved features in second-generation iPads recently unleashed on the world by California-based Apple.

"This is the biggest release we've had since last year when the iPad launched," SketchBook product line manager Chris Cheung said at a Digital Canvas exhibit of art made using the application.

"It is more productive and, as a by-product, it is more fun as well."

The software lets people blend and texture colors as they would with oil paints or other mediums. Movements of fingers on gadget touch-screens are converted into virtual brush strokes.

"This way, I have my whole art studio in my pocket," said San Francisco artists Julia Kay, whose works were among those in the exhibit.

"If I get bored I can lean against a wall and make drawings in full color, every texture, and I don't have to clean-up afterward."

Works by 82 artists were featured in the Digital Canvas exhibit in the Autodesk Gallery in downtown San Francisco.

Along with professional artists there were SketchBook users whose day jobs ranged from grade school student and farmer to surgeon and aerospace technician.

Matthew Hall of Britain described studied at Winchester School of Art and Chichester University but veered away from painting for a decade while he focused on video. The he saw artists working on iPads.

"Now I take my iPad everywhere, using the SketchBook Pro app to capture what's happening around me or what's banging around in my head at the time," Hall said in a description of his work on display at Digital Canvas.

"Like the primal cave painters we are just creating lines on a surface with our finger," he continued. "I haven't enjoyed doodling this much since I was a child."

Jay Shuster, art director for the "Cars" film sequel about to be released by Pixar Animation Studios, said he did almost all the character design using Sketchbook Pro and credited the software with enabling him to work fast.

"Every day, ever hour counted," Shuster said. "I think, in a way, going digital allowed us to finish 'Cars 2' in the time we did."

He worked with SketchBook software on a Pixar-supplied tablet made by Fujitsu. California-based Autodesk specilizes in 2-D and 3-D design software.

SketchBook Pro versions tailored for iPhones, iPads, and iPod touch devices were priced at $5 at Apple's online App Store.

Autodesk also upgraded a version of the software tailored for gadgets powered by Google-backed Android software, according to Cheung.