Making Drone frame questions - dimension linear tool, export format STL, extrude 3d, snap weld tools

[mmurakami500]

Hi, I am a senior VFX aritst who knows a fundemental for 2D/3D sfotwares, but a beginner for AutoCAD.

Using AutoCAD 2022, my procedure is:

1 Draw 2d drone frames. Parts can be only 2-3kinds, relatively very simple shape.

2 Apply thickness for some parts as carbon frames, and do a simple/quick 3d-models for TPU/plastic objects.

3 Make sure those parts are consistent in 3d space.

4 Export  DWG for carbon frame and STL or STEP files for TPU object.

Then, I have multi questions.

A

When I use a dimention linear tool, sometimes that text parts are gone, although I tried to modify Text height from 0.0001 to 9999.  How can I get back the text??

no dimention text

B

Because of a beginner, I sometimes noticed I did double copy and placed twice, and lines/curves are doubled. Do we have a tool which lines are doubled and how to remove those wasting lines? 

left is double circles and right is single circle

C

The below drawing is an example from a friend. This drawing is made with 5 lines, and each start/end are just snapped. Is this common way to draw in CAD?  This is because I must connect/weld start-end points in a 3d software like Blender when I am creating a 3d-model. 

D

There is a polyline?! object, and I think accidentally converted it. Can I convert back to spline object? PEDIT shows spline command/option but seems to not working. So I guess this covertion is one way...

polyline object

E 

When extrude drawings, simple circle line creates 3d volume objects, but my drawings are not working properly (E1). Next I joined all curves and apply Extrude(E2). Then object is gone!!

What's the requirement to be able to 3d objects? 

E1

E2

E3

 

F 

Eventually should I switch to use Autodesk Inventor?? Or AutoCAD will handle my goal?

Thank yo so much for your assistance!!!!

[imadHabash]

Hi and Welcome to AutoCAD Forum,

Would you please attache here your CAD dwg to give you a direct answer?

[mmurakami500]

To imadHabash
Thanks for your quick reply!! So I solved a couple of problems, but got some new questions too. 

I attached a dwg file and new screencapture png showing new summarized questions, totally 6 questions. Hopefully my questions are clear, and you would find answers quickly, thanks!!