linetype issue

why is it when i am some drawings, that when I try to change the lineweight or linetype, nothing seems to happen, and then in some other drawing when i try it the line magically changes?

new user and stumped on this one,

many thanks to someone with an answer,

oh yeah, is it something to do with LTSCALE?

Have you looked at MSLTSCALE?

Check to see if the "show line weights" button at the bottom of your screen is clicked. Not sure if the last setting is carried by the drawing or the workspace profile. If this is turned off you will NOT see a change in the line weight. This has nothing to do with how they will plot out. Even if it is turned on, sometimes you will not see a change in the line weight if your choice of weight is smaller than the program will display, around .025 mm. At any rate, the line weights displayed on the screen are relative to each other and do not change with your zoom distance. The screen does not display the true line weight, but a ratio of thin to fat. However the weights are displayed on your screen, they will plot measured just as they are shown on the line weight select dropdown list.

Various Linetype settings.

LTSCALE - main setting sets all linetypes to larger / smaller scale to what your plotting at.

PSLTSCALE

MSLTSCALE

with both PSLTSCALE and MSLTSCALE set to 1 the linetypes will sutomattically scale as per viewport scale. (Usefull with 2 or more viewports of the same information at different scales.)

CELTSCALE - Sets current linetype scale on a per element basis.

My choice is LTSCALE 1, PSLTSCALE 0, MSLTSCALE 0, CELTSCALE to what im drawing usually 40 or 50 ish. But everyone uses this in different ways.

Also regen if things dont change!

thanks to everyone for your replies