Why and When Should You Edit Raster Drawings?

Why Raster Editing?

I’ll tell you

why…

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When you have a stack of these…

When you have a stack of these…

and you need to make some changes…

When you have a stack of these…

and you need to make some changes…

Raster Edit or Convert to Vector?

Lesson 1: What are raster files?

Raster image files created by scanners are composed of a series of dots or pixels. Simple black and white images utilize a single pixel per dot which is later compressed to reduce storage demands. Color and greyscale files commonly use 8, 16, or 24-bits per pixel .

Engineering drawings are typically saved as TIFF. Color/greyscale images frequently use GIF, JPEG, and TIFF. CALS G4 format is the military standard and sometimes, the PDF format is used as a wrapper to an encoded raster image file.

Lesson 2: What are vector files?

A raster image is not directly compatible with vector-based graphics found in today's CAD systems. CAD tools create vector graphics with attributes (lines, circles, and complex objects).

Vector files are defined by specific points in a coordinate system. A circle in CAD is defined by a center point and a radius. No such information exists for a circle in a raster file.

Ya got it?

Now don’t stop learnin’

Now don’t stop learnin’

Raster Editing is: Making changes to raster images without converting them into another format

Now don’t stop learnin’

Raster Editing is: Making changes to raster images without converting them into another format

Vendor approaches to Raster Editing

Now don’t stop learnin’

Raster Editing is: Making changes to raster images without converting them into another format

Vendor approaches to Raster Editing

Simple paint-based: editing of the pixel dots, some basic CAD-like drafting for additions. Ideal for simple changes

Now don’t stop learnin’

Raster Editing is: Making changes to raster images without converting them into another format

Vendor approaches to Raster Editing

Simple paint-based: editing of the pixel dots, some basic CAD-like drafting for additions. Ideal for simple changes

Intelligent: raster-to-vector conversion techniques to feel like vector editing but in pure raster format. Move line endpoints, resize circles, and more. Productivity much closer to CAD.

Now don’t stop learnin’

Raster Editing is: Making changes to raster images without converting them into another format

Vendor approaches to Raster Editing

Simple paint-based: editing of the pixel dots, some basic CAD-like drafting for additions. Ideal for simple changes

Intelligent: raster-to-vector conversion techniques to feel like vector editing but in pure raster format. Move line endpoints, resize circles, and more. Productivity much closer to CAD.

Hybrid: CAD drafting tools for all geometry additions, save changes in pure raster or a combined raster/vector file format. Beneficial if incrementally converting to vector format.

Now why on earth

would you want to edit raster instead of convert to vector?

Just sit there in the corner and I’ll tell you.

Just sit there in the corner and I’ll tell you.

Raster is universal: vendor, version, and revision level independent . As CAD software is obsoleted, maintaining as raster ensures usability well into the future.

*

Just sit there in the corner and I’ll tell you.

Raster is universal: vendor, version, and revision level independent . As CAD software is obsoleted, maintaining as raster ensures usability well into the future.

*

Raster data is easily viewed by standard viewers on most PCs. *

Just sit there in the corner and I’ll tell you.

Raster is universal: vendor, version, and revision level independent . As CAD software is obsoleted, maintaining as raster ensures usability well into the future.

*

Raster data is easily viewed by standard viewers on most PCs. * Raster files are 30 - 50% smaller than vector files. *

Just sit there in the corner and I’ll tell you.

Raster is universal: vendor, version, and revision level independent . As CAD software is obsoleted, maintaining as raster ensures usability well into the future.

*

Raster data is easily viewed by standard viewers on most PCs. * Raster files are 30 - 50% smaller than vector files. * Conversion to vector can be time consuming, cumbersome and requires special software and trained personnel *

But what can raster editing really do?

*

Grid and ortho snap for accurate insert

Move, copy, scale, and rotate selected or new raster

Add basic geometry such as lines, circles, arcs, and rectangles

Insert raster drafting objects such as text, ellipses & polygons

Some systems can edit raster pixels with the intelligence of being vector objects

*

*

*

*

and… *

Erase areas using rubout, rectangle area, polygon windows, and circle & ellipse fills

Undo multiple levels to repair undesired results

Enhance or clean up including deskew, despeckle, crop and adaptive thresholding

Fill patterns with cross hatch, translucency, border styles and varying pen widths

Support measurements, leaders, calibration, and dimensions

*

*

*

*

Don’t believe me?

Moving a line with a raster editor

Measurement of an object length on a raster drawing

Cleanup with adaptive thresholding of a drawing

Added rectangle, circle and text object to a raster drawing

QUIZ TIME!

Should I raster edit scanned drawings or should I convert to

vector?

Just use your brain!

Just use your brain!

There is a time and place for both.

If: Raster Editing

Simple Drawing

Convert to Vector

Complex Drawing

If: Raster Editing

Simple Drawing

Simple Changes

Convert to Vector

Complex Drawing

Complex Changes

If: Raster Editing

Simple Drawing

Infrequent or Frequent Changes

Simple Changes

Convert to Vector

Complex Drawing

Frequent Changes

Complex Changes

If: Raster Editing

Simple Drawing

Infrequent or Frequent Changes

Simple Changes

Untrained Personnel

Convert to Vector

Complex Drawing

Frequent Changes

Complex Changes

Trained Personnel

If: Raster Editing

Simple Drawing

Infrequent or Frequent Changes

Simple Changes

Untrained Personnel

No Budget for CAD

Convert to Vector

Complex Drawing

Frequent Changes

Complex Changes

Trained Personnel

Budget for CAD

So where do you go from here?

GTXRaster CAD® Series - longest standing solution as a raster editing and vector conversion solution for use within AutoCAD. Supports all current AutoCAD® versions. Windham Document Systems AutoCAD® Raster Design by Autodesk® - hybrid editor and raster-to-vector conversion tool that also works within AutoCAD. Autodesk

ReVisa from DocuFi is a simple and fast PDF and TIFF raster editor which can meet most raster editing needs. DocuFi ReVisa GTXImage CAD® Series - OEM version of GTX along with a 2D AutoCAD license. It is a full hybrid editor, raster editor, vector editor, and raster-to-vector converter which utilizes the AutoCAD 2D engine. Windham Document Systems

Now go do your homework!

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