still needing help with projecting curves

kees_bijker

Trying to apply the projected curves from the learning center excercise in a real life situation, and I am immediately stuck!

https://cad.onshape.com/documents/4abb0be366f56a87d806a695/w/ade8802c4b0bce16522a09b9/e/4b90e895ae62ae320b3c3428

In this document I have added 2 photos, one top and one front view, and I have added 2 sketches, one for each. As the start point I used my existing rocker box to line the photos up to, but once I try to project these two curves t doesn't even allow it. I moved the boxes, and scaled them, as to line up with the model, so I expected to find some of these curves to share a point, but it does not seem the case.

How do I work with real life photos to take curves from that will ultimately allow me to make the shape that resembles the real part? I have followed several "at my own pace" instruction videos, but in these videos you are given examples that obviously work and the "perfect" instructions tell you exactly how to place the images for them to work. What is missing for me is the link with real life, where your photos start as two unrelated entities and may not match eachother exactly, even though they are of the same object!

Please any hint as to what I should be doing differently would be greatly appreciated, as always?

Have a nive holiday season everyone!

Kees

kees_bijker

I tried another approach whereby I ignored my own part and focussed only on the photos. I tried matching op one equal point on each photo, which I placed on origin, and then scaled the second photo to match the size of the first one.

I did get some slightly better result, but still not what I expected.

https://cad.onshape.com/documents/4abb0be366f56a87d806a695/w/ade8802c4b0bce16522a09b9/e/a24ed39a1b5b4fe760a4657e

Please some hint from a person who knows what I am doing wrong?

Matt_Shields

I have two hints from my limited experience with curves and surfaces.

1. The goal with the curves is to create the underlying curves that will eventually be use to build the desired surfaces. So, as you're making curves (projected curves, 3d fit splines, etc.) go at it with the intent of creating boundaries and guides that will eventually guide your lofts and other surfaces.
2. I have more luck with projected curves when using smaller subsets of the entire traced envelope (see below).

kees_bijker

https://forum.onshape.com/discussion/comment/111339#Comment_111339

so from what can see from your example, you would choose two open curves from two profile photos and make an open projected curve from those.

Then I suppose you would do it again with this curve and another from a third profile.

Then another view again and so make curves for your surfaces.

Does that sound right to you?