Hi friends       Plz explain how to change base point of a block.The block is inserted in several places in a drawing otherwise i can explode it and create new block.Plzz help me..

You have a couple of options, depending on what you really want to do.1.  If the block has an inconvenient basepoint location and you want to change it to somewhere else, open the block editor and make sure the Block Authoring Palettes (BAUTHORPALLET at the command line or from the ribbon) is open.  Select the Parameters tab and then put a new Basepoint parameter in the block where you'd like it.2.  If you want to make a block with *multiple* insertion points (many basepoints if you will), follow all of Step 1 above, but instead of selecting Basepoint, select the Point parameter.  Put Points in where ever you might want an insertion point for the block.  Then when you insert this block, tap the Ctrl key to cycle thru the different alternate insertion points until you get the one you need.Dave.
heinsite2013-01-24 07:59:44

From the website of Ellen Finkelstein noted AutoCAD author:"Use the BASE command in the drawing containing the block to specify the
origin of the drawing, which is usually on an object snap somewhere on
the block. Then, when you insert the drawing, your basepoint will be
right on the block."

here is what i use, it's the easiest and the quickest way of doing it.use command and type "bedit" and "enter" it will take you there for block editingthen slect all and pick the point (i usually turn object snap on, to get the exact point) and move to "0,0,0" location.then exit and save.that's what i found, it's quickest and easiest way (it might not be the right way).

[QUOTE=power22200can]
 
then slect all and pick the point (i usually turn object snap on, to get the exact point) and move to "0,0,0" location.
 
[/QUOTE]
 
Here is where this idea runs into trouble:  Let's say you've been working in a drawing and you decide you need a block.  So you draw the object in the model.  Then you select it and enter the block editor.  When you originally drew it you were FAR from 0,0... maybe somewhere out like x=150,000 and y=250,000.  This is not uncommon.  Then you finish and save that block with the basepoint at 0,0 without noticing the coordinates on your object.  Oops. 
 

What do you suppose happens now when you insert this block somewhere else in the drawing and you check the box for "Specify on-screen"?
What happens if you turn the "Specify on-screen" checkbox off and insert?
 
Answer:  Problems either way.
 
If you are planning on xref'g drawings as blocks into other drawings, everything should be referenced to a common 0,0 basepoint, yes, because it's like pin registration.  And if you create your original block geometry entirely in the block editor somewhere close to 0,0 you can use 0,0 and get acceptable results.  But if your object geometry is out in the boonies there's trouble up ahead!  In general, blocks should have a basepoint somewhere on their geometry or things can quickly run off the rails. 
 
Dave.heinsite2013-01-25 03:44:46

could you please upload the block and mention where you want to put base point on it, so i can see why it can't be done? 

It's not that what you're doing won't work, it's mostly that the "move" portion of the process is completely unnecessary.  You can use the Block Authoring Palette to place a basepoint parameter anywhere you want on the block without worrying about where you are in coordinate space.Dave