Part Design Help?

[dgoocntzoor]

Hello,

I am new to freecad. I'm looking for a few pointers on how to create a tear drop like part. I have worked on this for a while, it resembles a tear drop, however it is kind of messy. Maybe there is another method that would make designing this shape easier? Currently I am using points and circles formed on the xyz axis in draft, then the utility to loft in part. The problem I am having is getting the bottom round, and the sides to be smooth. I have tried moving the circles around by little bits, but just can't quite get the smoothness I am looking for. Any suggestions? I have attached a screen shot.

[chrisb]

Please follow the link "IMPORTANT: Please click here and read this first, before asking for help" above. It has a red background and is hard to miss. Please read especially point 3 about your FreeCAD version and point 5 about attaching Word documents.

If you are willing to try the development version 0.17 you have bsplines in the sketcher which might well suit your needs. If you use 0.16 you can use the Part Design Workbench as well with circles of different radii. Smooth the connection with tangential constraints. If you create a sketch with the half of a sectional cut you can rotate the drop afterwards.

[dgoocntzoor]

My fault, I have not seen those before.

I am using version .16.

I have tried that, the problem is that I can not join the lines/points if I go that route, the boxes are grey'd out, so that function is unavailable. I have attached both sketches to this.

[chrisb]

You seem to miss the basic handling of the Part Design Workbench. Please have a look at and work through some of the tutorials. There are excellent video and written tutorials to your taste.

To connect the two arcs: Move the arcs in a position to be near to your needs (you have done so.) Select the endpoints to be connected, they turn green. Click the tangent constraint.

For the rest: I added a coincident constraint on the lower arc center and the coordiante systems center. Added a tangent constraint on the upper arc and the Y axis, constrained diameter and height, added a rectangular constraint at the bottom and a connecting line from bottom to top. (Writing this took more time than fixing the model)

Keep in mind what I said before: Model only half of the section, the other half is created by the rotation.

[Willem]

Hi. welcome to Freecad and the forum

Using lofts for your raindrop is possible but in the properties you have to make it solid, see image and the bottom of the loft can be given a fillet

Schermafdruk van 2017-04-28 00-19-34.png (255.81 KiB) Viewed 1237 times

A second possibility is to make a sketch with a path
Draw in the draft workbench a circle at bottom of the path
Draw in the draft workbench a point at the top of the path
Create a sweep in the part workbench
Make a fillet at the bottom in the part workbench

[dgoocntzoor]

Building half the model seems to help. I have the shape I want now, but I can not figure out how to rotate it. Is there an issue because I am working with curved lines? Or do I run a line through the middle and rotate it around that? Also, I keep getting a solver message of "Under constrained sketch with 17 degrees of freedom" - If I add other constraints I just get more errors now. Attached the new sketch.

[dgoocntzoor]

I just realized that didn't save.

[dgoocntzoor]

Now that I have the under constrained sketch with 8 degrees of freedom, I can not save the sketch, it deletes it. I can also not figure out where the constraint needs to go.

[Willem]

Hi, here is an example of a full constrained sketch, but it is not possible to use it for making a raindrop

Schermafdruk van 2017-04-28 16-16-49.png (242.67 KiB) Viewed 1204 times

To make a raindrop you have to make a sweep along a curved path as I advised you in a previous post

[dgoocntzoor]

Thank you for the quick reply. I can make the drop like you did in the previous post. Is the shape I am trying to make not possible?