AutoCad 2018 Subtract and SurfTrim Issues with Text

[Anonymous]

Hi, I'm having a huge issue with some 3d text currently that won't Subtract or Surf trim from an IPhone case I found online that was made with SolidWorks. The IPhone case was originally a SLDPRT file that I then imported into AutoCAD 2018 Student Edition. I currently have made text that says "Innovative Design Studio" as I was hoping to add that to the back of the case. I cannot get either to work though however. It seems depending on where I mouse over the text that it is either a 3d model or surface. The Case under LIST is a 3d Object. I am new to AutoCAD, but it seems to be an easy thing to do however I'm sure that I am making a very easy mistake. Any Help would be appreciated. I have attached my .dwg file. 

[Alfred.NESWADBA]

Hi,

you first need to create a 3D-Solid from your letters, then use command _SUBTRACT to cut the letters from the case.

- alfred -

[Anonymous]

Hey Alfred!
I started out with Mtext and then exploded the letters. From the explode I then extruded them to a .5 heigh so they would go through both ends of the phone case. However the _Subtract command is still not working.

[Alfred.NESWADBA]

Hi,

>> From the explode I then extruded them to a .5 heigh

Whenever you extrude non closed polylines you'll get surfaces as result.

If you first close the polylines you've got from the text then you'll get 3D-Solid objects.

HTH, - alfred -