Expression "VIEWSCALE" did not match with the map view scale.

[laikuntaoALZN5]

1. Create a drawing layer.
2. Style the drawing layer with Symbol, select the block for the layer, then the blocks were inserted.
3. Set the block scale "(VIEWSCALE)"
4. After setting map the view scale like "1:10000", I found the blocks' scale wasn't the same as the map view scale set before. The block's scale is 6.9444.

How to calculate the expression "(VIEWSCALE)"？Why didn't the blocks' scale match with the map view scale?

Please give me some hits. Thanks a lot!

[ChicagoLooper]

Hello @laikuntaoALZN5 

You are confusing VIEWSCALE with your block’s annotation scale. 

While on a LAYOUT TAB you can control the  VIEWSCALE when you activate the viewport in order to establish the VP’s zoom factor. Once you’ve selected the appropriate VP scale, it’s a good practice to lock the viewport.

<<If you change your mind, unlock the VP to change the scale, then relock it after the revised VP scale has been selected.>>

Also, while in MODELSPACE, you can control the appearance of your annotative objects—objects such as your annotative block, by using CANNOSCALE. You can achieve this by selecting a ‘named scale’ from the scales listed in the dropdown (near the clock) on the Status Bar. 

<<If you want to use a scale that’s not listed, then you’ll need to add a new scale. AutoCAD likes to confuse you by making you ‘customize’ this list in order to ‘add’ a new scale.>>

The VIEWSCALE controls the appearance of your printed sheet (or the ratio of paperspace units to modelspacespace units), commonly called viewport scale. 

Don’t neglect the drawing scale, CANNOSCALE, that you establish while in modelspace—it controls the drawing environment, which in turn controls appeance (size) of your annotative blocks. 

Generally speaking, make CANNOSCALE in modelspace and VIEWSCALE set from your layout tab the same scale. 

<<You may need to enter REA (regen all) on the command line if you decide to change scales.>>