Problem creating a patch from projected lines

[Anonymous]

Hello all,

I have a problem trying to create a patch?  I have researched online a lot about this and done some tutorials in surface modelling so I'm pretty sure it's a patch that I want.  I've gone this route because I need to be able to adjust the splines later if need be and I need a G2 blend with the main body.  I can get a loft to work but it won't allow me to create the G2 blend.

The connection lines had to be created by projecting geometries and they appear to be fully connected and in the correct positions.  However as soon as I try to create a patch it will not even let me select both sets of lines and the ok button is always greyed out.

Any help and direction would be appreciated!

Thank you!

[TheCADWhisperer]

I noticed that your sketches are not fully defined?

I noticed that there are a lot of nodes in the spline and it is not symmetrical?

I noticed that a simple projected circle closely matches the spline (well within any possible manufacturing tolerance).

I noticed other issues as well, but let's start with these.

What are you attempting to model?

[laughingcreek]

a few more thoughts-

you not going to get a patch to a sketch line g2 to anything.  is there a reason your not using the surface edge?

what's up with the white dot?  is it part of your patch geometry?  should be coincident to something.

probably need to see the model.

[Anonymous]

Thank you for taking the time to look at this, in answers to your questions:

I noticed that your sketches are not fully defined?

I'm not actually sure what 'fully defined' is referring to?  I had hidden a large amount of the geometry in the drawing to make the splines I was highlighting stand out.. not sure if thats what you mean't

I noticed that there are a lot of nodes in the spline and it is not symmetrical?

The nodes appeared automatically after I projected them?  projecting was the only way to get the connection lines onto the curved surfaces?

I noticed that a simple projected circle closely matches the spline (well within any possible manufacturing tolerance).

The 'bitten off' curve is in fact a projected circle from the xy plane below.

I noticed other issues as well, but let's start with these.

I'm trying to copy/ model an item that was originally made in metal but I'm intending to 3D print it.  It is subtly quite complex and it will probably take a few attempts to get close - it must fit into another component and also look right so I need to be able to play with the surfaces and how they blend with each other.

[Anonymous]

Thank you for your thoughts - 

just to mention first the model file should be there for you to download if you like to take a closer look?

Ok so I should be able to patch directly to the 'cut out' edge? (yes the purpose of the projected line is just to establish the point where the patch must meet)  I did actually try this but it didn't seem to work either.

Not sure about the white dot, I'll investigate thanks!

[Anonymous]

OK just to mention I have sorted the 'cut out' edge by simply extruding up a circle and cutting it out rather than using the projection - this does look a better edge now and is a far more straightforward way to do it thanks!  

However it still won't let me us the second projected spline to create a patch, I'll continue working at it to see if there's a different way to recreate it.

[Anonymous]

I have cleaned up both edges now simply by using extrude and trim commands, but it still won't allow me to patch?

Is there something I'm missing?

[laughingcreek]

sorry, didn't see the original attachment.

when I looked at it, the ends of the curve you where patching to weren't actually coincident to the edges of the surface/projected lines.  which is why you couldn't patch, you didn't have a closed loop.

may still be the problem, can you post your latest attempt?

but I suspect the approach your taking may be overly complicated.  can you post any information of what your trying to achieve (pics)?

[Anonymous · Accepted solution]

Thank you for your help - yes the good news is I've actually just succeeded with what I wanted to do -

So the problem was that it wasn't seeing it as a closed loop, although as far as zooming in and setup was concerned everything was coincident.

I solved it by moving the tool surface away (based on the corner point) and then repositioning it as coincident using the point to point option.  As soon as I did this it worked and I now have G2 also.

Thank you all for your contributions and advice!