Tag: image

Take the Guesswork out of Scaling an Image in Revit

Luke Johnson

After inserting an image in Revit, sometimes the X and Y (Raster Image Width and Height parameters) values of the image are somewhat “warped” and need to be adjusted to match your model background.

I created a Line Based Detail Item family that generates a scaling factor that can be used to properly warp the image aspect ratio.

Just untick Lock Proportions, type an = sign in front of the value that needs to be warped and then put an asterisk (meaning multiply) followed by the Scaling Factor that the family generates.  It will look something like:
=34542.8*1.056

The image below explains it further:

Download the Family here

What is your favourite image editing program?

Luke Johnson

Some of you may be surprised to know that Windows Photo Viewer and Office Picture Manager are not the only ways to view and edit image files 🙂  Here are three of my favourites:

1)  Irfanview has been updated to version 4.35.  You can download from CNET here.  This is a superfast image viewing and editing program.  I love it for its highly adjustable batch image processing ability.

You can download all the current plugins from here.  This includes a new plugin that will allow Irfanview to open DXF files, as per this list.  The DXF plugin is provided by BabaCAD – they also provide free CAD software for download at http://www.babacad.com/index.html

2)  Paint.NET – quick and easy

3)  Photoshop – awesome filters and effects, and great at enhancing still photos of your buildings

4) GIMP – Andy Milburn reminded me about this in the comments.  I haven’t used it for a long while, but it is essentially a free replacement for Photoshop.

5) pixlr – another great tip from the comments.  RicardoCC referred me to this online image editor that was actually purchased by Autodesk.  Have you tried it yet?

Export render from Revit and quickly put background on a different layer

Luke Johnson

The Revit Kid demonstrated today that PNG files exported from a Revit render have no background.

In the spirit of one-up-man-ship, I recommend that you use TIF if you want to keep the background, but quickly separate it from the model elements.  When you export as TIF, you get a bonus Alpha channel that you can use to create a selection area and move the background to a new layer.

In simple terms:

  1. Export Revit render as TIF
  2. Open in Photoshop
  3. Isolate the Alpha channel
  4. Use Magic Wand to pick everything that is ‘white’
  5. Turn the color channels back on
  6. Invert the Selection
  7. Convert the background to a true layer
  8. Edit – Cut
  9. New Layer
  10. Edit – Paste
  11. Done!

Now you can manipulate the model elements and the background separately.

Here is a video:

 
Of course, you can also do this easily by:

  1. Doing two separate renders, 
  2. one of them with Model Elements turned off (which will just show the background) – Export this to any format except PNG
  3. and one of them with Model Elements on (export this to PNG)
  4. Copy and paste these two images to separate layers in Photoshop

 The TIF method is probably quicker and easier in most instances.

Here is a link to the aforementioned PNG post:
The Revit Kid.com!: Revit Tip – Export Rendered Images Without a Background

Search by Sketch

Luke Johnson

I had this great idea this morning – why can’t we do a ‘search by sketch’ of images or other data?

In other words, you draw a small sketch of something, and then the search engine returns results that are similar to or related to that sketch.

First I thought ‘quick, I better blog about this, before someone else does!’, but then I thought, ‘I better see if this exists yet…’

And, it does. Have a look at retrievr. I did not have great results when trying this out, as it is ‘experimental’.

If you want to search through some 3D models using a 2D sketch and keywords, have a look at Princeton 3D Model Search Engine.

There is a paper written on the subject. It is called 3D content-based search using sketches.

The next logical question is – is there some software that I can download that can perform this search on my own images?

Check out the vid below:

For more information, check out http://www.chrisharrison.net/projects/searchbysketch/index.html.

I foresee a time (in the not too distant future) when a full blown image search engine will be available, that takes either a sketch or uploaded image as input, and returns a list of images in order of similarity. Perhaps you can also specify a ‘tolerance’ value, that filters out the least similar and simply does not show them.

If you know of any technology or software similar to this, please comment.