Set Transparency on a new Layer

[mmP3TWV]

Is it possible, tat I can not directly Set the property Transparency when I generate new layers but have to create my layer first and change  the Transparency later? 

Tried with 

(CREATE-LAYER "Gebäude_Schraffur" '((COLOR . 253) (DESCRIPTION . "01211F") (LINETYPE . "Continuous") (LINEWEIGHT . "20") (TRANSPARENCY . "50")))

And got a Message that Transparency was unknown  

[ВeekeeCZ]

Post CREATE-LAYER function to take a look

[komondormrex · Accepted solution]

layer transparency has to be set via extended data.

[paullimapa · Accepted solution]

Thoroughly discussed here 

https://www.theswamp.org/index.php?topic=52473.0

[Kent1Cooper · Accepted solution]

If you just use an ordinary LAYER command in an AutoLisp (command) function, instead of a specialty routine, it's easy, and does not require going into extended data:

(command "_.layer" "_make" "Gebäude_Schraffur" "_color" 253 "" "_description" "01211F" "Gebäude_Schraffur" "_lweight" 20 "" "_transparency" 50 "" "")

Oddly, the default-on-Enter Layer application in the Description option is not to just the current Layer as with most options, but to all Layers, so it's necessary to spell out the Layer name again for that.

The numerical entries do not need to be as text strings.

It is not necessary to assign Continuous linetype to a new Layer -- that is the default.

[Also, I spelled out the option names in full, but if you use the abbreviations, it takes less code than the specialty (CREATE-LAYER) function needs.]

[mmP3TWV]

Thank You all for the great support on this topic. I will give the extended data a try as I need to build a ton of new layers and like the tidiness of the specialty routine. But the command function is a welcome backup.

[mmP3TWV]

I work with  the basic solution from autolisp.info with subfunctions.

; Erzeugt einen neuen Layer
(defun create-layer(name props / newlayer)
  (setq newlayer
    (vla-add (document-layers) name)
  )
  (foreach prop props
    (vlax-put-property
      newlayer (car prop)(cdr prop)
    )
  )
  newlayer
)
        

https://activex.autolisp.info/layreactor.html

[komondormrex]

funny thing, but the layer transparency could be set beyond 90% limit using xdata.

[Sea-Haven]

"I need to build a ton of new layers" for me make Kents solution a (defun and pass it name, color, linetype, transparency. For a 100 layers I would use a csv file hence the hint. Just read the file. You can save all the info in Excel and make the csv file. Even using command will still be fast. I would do a (princ layname) as you read a line so you can see something happening.