How to make concave parts in Autocad?

Take a look at the attached dwg, set UCS to front and draw your shape (red), make it into a polyline - I just trimed circles and joined them. Change the UCS to left (or right) and draw the curve (yellow), then draw an oversized line (green) from the base of your leg that extends beyond the curve. Use the array command with the options -path, method, divide, items, I chose 51. select the curve yellow and use the trim command to trim all the lines. Then draw a spline that uses the end of these lines as fit points. From there you should be able to extrude a circle around the spline.

Chair.dwg

oh my god, i hope this will help me to all my confusion. thanks ReMark. will go it through NOW!

yes, i actually remembered about what JDM said in the earlier post, and honestly, i've been searching but to no avail cuz this community is kinda big. haha

i also remembered about the thing he said about "projecting", but not sure how to accomplish that.

hurmm, let me try to clarify that, from the picture

image upload no size limit

lets say i want to model a skateboard, the white sketch is my base design, and the red line is a curve i want it to be, is there any way autocad can achieve this?

if the red curve is a polyline, offset it the thickness you want the board to be, connect it with lines and pe (polyline edit) it to a closed polyline. Extrude the red and white polylines one at a time so the solids cross, then use the command intersect.

...remembered about what JDM said in the earlier post...

INTERFERE Command

or PROJECTGEOMETRY Command

See how helpful everyone is? And you were worried. LoL

More than one way to accomplish a task.

wow, that is a lot of ways to accomplish this task. thank you everyone

@steven-g - now i dont have to manually draw a vertical lines. thank you

@zaphod - a lot of things can be accomplished by that method. thank you

@GP_ - i learnt 2 new commands today because of you. thank you

@ReMark - i wasnt worried okay! just a little stressed because more than a week searching any tutorials related to this. i guess joining this community helped me a lot! yay~!

but sadly, i cannot practice any of em right now, going out of town tomorrow, and i havent packed my things yet (11:20 pm now).

see you in a few days with a little bit of improvements and more problems i think. thanks again Sifu

hi everone, i am back.

as suggested by GP_ , i tried making a board using the projectgeometry command, projecting the geometry to a surpace that i made from the side view was a succes, but when i try to extrude it, instead of becoming a single solid, it only produces a vertical surface along the lines. but by using the patch tools in the surface tab, i managed to close the hole between it.

what have i done wrong making it only extruding a surface such as in the picture.

any help is greatly appreciated.

When you made the profile of your skateboard did you use lines and arcs?

What command did you use to give the skateboard height? My guess is Extrude. Is that right?

SURFSCULP command

@ReMark - yes, i made a base line, and then a

@GP_ - again, new command taught by u. thank you.

quick question: is there anyway to fillet a polyline and arc? (Found it, tan tan rad fixed it