AutoCAD Layer Freeze/Thaw vs On/Off

Many AutoCAD users have a confusion about the use of freeze (LAYFRZ) and turning a layer off (LAYOFF). While both commands have the basic function of making a layer invisible, there are certain differences between the two.

Layer freeze vs off

Turning a layer off (LAYOFF)

  • Objects in the turned-off layers are still selectable using commands such as  SELECTALL.
  • REGEN command  regenerates all objects including the objects in turned off layers.
  • Zoom extents considers turned off objects as a part of the drawing.

Layer Freeze (LAYFRZ)

  • This command completely turns off the layer. Layer is  not selectable.
  • Frozen layer does not have any effect on REGEN command.
  • Zoom extents does not recognize frozen layers as a part of the drawing.

How to design an energy efficient Home

“Green building”  in other words, Sustainable design, is a fairly novel idea which came in to light in 1980 and has dominated the modern building design industry. Basic idea behind this concept is increasing energy efficiency of buildings through its design.

Location is everything
Solar access throughout the year sample design
-Choosing a land plot facing north allows harnessing of  less intense winter sun rays. Also, organising the build layout in such a way that living and other common areas facing north, can significantly reduce energy costs.

The location
-Before choosing the location it is important to be aware of local climate conditions such as Temperature ranges and seasonal characteristics.
-Rectangular plots often permit most efficient land use.
– Sites running N-S with good solar access are ideal.(20- 30 degrees of true north is considered acceptable.)

The house
-Living areas should be north facing with good access to winter sun.
-Zone areas with similar heating needs. (Living areas facing north, bedrooms/store rooms in facing south. etc.)
-Glass shading, locks in the radiant heat inside the building which is desirable for winter heating.
Locking up the winter heat
-Proper insulation prevent the unnecessary heat loss – AS/NZS 4859.1:2002 (incorporating amendment 1)

Standard for shading

  • North – Fixed or adjustable shading  placed horizontally above the window
  • East and West – Adjustable vertical screens outside the window
  • SE and SW – Planting (Use deciduous trees to the north and evergreen trees to East and West)

Material Use
Using various construction systems can minimise the embodied energy of the building
Few important construction systems are;

  • Mud Brick (Adobe)
  •  Rammed earth (Pisé)
  • Straw Bale
  • Lightweight timber
  • Clay Brick
  • Autoclaved areated Concrete (AAC)
  • Concrete Slab Floor
  • Green roofs and Walls

For more information

BIM (Building Information Modelling)


BIM, if not Building information modelling is a concept that came in to existence in 1970 which involves generating and managing a digital representation of a building. In other words, this whole concept is about creating a virtual building inside a computer and using it to extract information such as light analysis, geographic information, quantities, cost estimates, and properties of building components. material tracking and ordering etc.

Autodesk Revit and Graphicsoft ArchiCAD are among the leading software packages which are widely used in BIM. Proficiency in Revit Architecture or Archicad are highly regarded by employers in Building design industry.

Programming a Wireless router to do what it’s not meant to do

dd-wrt interfaceThe other day I threw few bucks on an old P4 HP pavilion PC which was working very well on XP. Plan was to use it as an entertainment unit coupled with the TV to watch DVDs, access USBs, download PODs , and hopefully also to use as a satellite receiver.

Turned the computer on, Didn’t take more than few seconds for me to realise the first problem, Damn thing doesn’t have a WiFi card!.

OK,, Now I have two options,
One – Buying one of those low end wireless cards for $20 which is almost double the cost of the PC,
Two – Program one of my old wireless routers as a WiFi card.

Changing the router firmware
Any electronic device such as calculator, printer, microwave has it’s own set of operational instructions embedded in to its memory. Some of these have the ability to be reprogrammed.  For instance if a microwave is re-programmable, we could be able to make the plate inside rotate other way around or make the light inside flashing.

dd-wrt is a free open source Linux based firmware compatible with quite a few router brands. Installing dd-wrt makes the router multifunctional allowing it to perform many tasks such as;

  •  Hotspot Portal
  •  Client bridging
  • Linking routers
  • MAC address cloning
  • Wireless bridging
  • And much more

Changing the firmware is extremely easy if steps are followed correctly

Here is how;

  1. Download a recommended build for your router. DO NOT USE SP1. If you are using a broadcom router, read the peacock thread prior to starting. Use one of those recommended builds.
  2. Do a HARD reset on your router.
  3. Connect a cable from your computer to the LAN port on your router.
  4. Set your computer to a static IP address of
  5. Set your browser to and open the dd-wrt webgui.
  6. You should be asked to change your password and username. Carefully type these in. If you aren’t asked for a password and username, do a hard reset, this time doing it properly! Hit change password.
  7. Go FIRST to wireless, wireless security and enter the security type and key that matches your primary router.
  8. Hit SAVE, (or APPLY if you wish to)
  9. Go to the wireless, basic settings page and change the wireless mode to Client Bridge.
  10. Your wireless network mode, channel and encryption should be set to the same as the primary router.
  11. If you are using N only or Mixed with N, set your wireless channel width to match your primary
  12. Set the wireless network name to exactly the same as your primary router. Make sure spelling and capitalization match.
  13. Hit SAVE at the bottom. Then hit APPLY.
  14. Check to make sure all the configurations, including the mode, saved and the mode is still client bridge. If any changed, fix them, and save again.
  15. Goto Setup, basic setup and enter a router Local IP address of (Presuming your primary router is on the 192.168.1.x subnet. Client bridge must match the subent of the primary router) Leave subnet mask at
  16. Set the Gateway IP to your primary router. (Likely
  17. Leave Local DNS blank
  18. Check Assign Wan port to a switch, if you wish to.
  19. Change your timezone and DST to match where you are.
  20. Hit Apply.
  21. Set your browser to and login to your router
  22. Goto Security, Firewall. Under Block Wan Requests, uncheck everything but “Filter Multicast” (Leave Filter multicast checked).
  23. Hit Save
  24. Disable SPI Firewall
  25. Hit Apply.
  26. Go to setup/advanced routing and change the operating mode from “gateway” to router. Hit Apply.
  27. Set your computer back to auto IP and auto DNS.

You are done. Configure any other settings you wish at this point.

For  extra info

Atterberg limits test

Atterberg Limits test is performed in order to differentiate the state of the soil from the four main states of soil namely;

1) Solid
2) Semi solid
3) Plastic
4) Liquid

The test is performed using a apparatus called Cassagrande.
Testing procedure

1) Liquid limit : Water content where cut close at 25 blows.
2) Plastic limit : Water content at the point where 3mm threads start to crumble.
3) Plasticity index : LL – PL
4) Liquidity index : (w- PL) / PI

More information on soil types and classification;
AS1726,    AS 1289

Is it possible to install Windows 7 using an USB

The answer is YES;

There is a simple software developed by Microsoft which enables users to install Windows 7 on any computer with the usw of an USB, This is not only easy, also considerably fast.

Here is how;
1) Download Windows 7  in Iso format. (Read my other post if you are not sure what this is.)
2) Download the software from CNET.>

Windows 7  USB/DVD download tool


3) Run the software and follow the instructions; this will make a bootable USB,
4) Restart the computer >Go to BIOS > Booting order > change the booting order making “boot from USB” number one in the list
5) Exit BIOS and start thr computer > Stick the USB in the port > Restart > computer will ask to boot from USB > Enter >
6) Now computer will start copying files from USB to a temporary folder in the computer, after this step it will automatically start installing windows 7.

*** once files are copied and installing stated, force remove the USB to allow the computer to boot from the Hard disk at next automatic restart***

Note ; -The process will completely erase the USB drive, so make sure you don’t have any important files in the USB.

– Installing process involves the computer automatically restarting several times and  usually takes 15 -20 minutes.

Need help?

Keeping PDF files from expiring

I was always annoyed by the fact that PDF files I borrow from library expire after certain period of time, making it impossible to read.The apparent reason for this is the JavaScript, embedded in the PDF, which is programmed to expire the file after certain period of time.

Here is how to get around this ,

Adobe Reader

1) Launch Acrobat or Adobe Reader,

2) Select Edit>Preference,

3) Select the JavaScript Category,

4) Uncheck the ‘Enable Acrobat JavaScript’ option

5) Click OK.

Foxit Reader

1) Tools >preference>Javascript

2)  Uncheck “Enable Javascript actions”