can't fillet of face blend

dominique_charmot

I have been dabbling with complex surfaces as a woodworker hobbyst and, while I can fillet edges in simple construct, I can't make it work in complex surfaces. In the latter case I can only make it work withe the "detached" box checked, which does not really help.

Here is an example: I try to create a fillet between the grey leg and the golden back rest and all failed. The grey leg is generated by a loft whose end profile is "buried" within the back rest. I then combine the two with a boolean operation (to create an edge at the junction of the two parts). Can anybody give me pointers as to what I do wrong here?

thanks

https://cad.onshape.com/documents/2c8fb0010ef2fb0e7f44a81a/w/a7fb163b52bfdfa400ca8bf6/e/1239f79774cf5fe2032be86f?renderMode=0&uiState=670d3a123711ca4e0a4fcf1e

MDesign

https://forum.onshape.com/discussion/comment/108331#Comment_108331

You have a lot of extra doodads going on in there but I just boolean'd arm back rest and upper back leg then applied a fillet. It has a limit in size of about 4.6mm because the seams on do not meet perfectly (you have to make sure to select that little line shown in pic since its not tangent). and it gets confused at that transition. When in doubt try a tiny fillet. if it works then go bigger and bigger till you find the trouble spot usually highlighted in red. If your sold on face blend. it will probably have the same issues at those points I didn't try face blends. Simple answer is don't waste your energy on creating edges to fillet when boolean or other tools will create those edges for you. So when your loft end is inside the the other part just boolean it together. no need to trim it back to meet up with the other part. Hope that make sense. If not let me know.

_anton

The grey and gold parts aren't actually booleaned together, so there's no edge to fillet between them.

dominique_charmot

Ooops, I just restored the boolean. However the problems persist….

https://cad.onshape.com/documents/2c8fb0010ef2fb0e7f44a81a/w/a7fb163b52bfdfa400ca8bf6/e/1239f79774cf5fe2032be86f?renderMode=0&uiState=670d67ebc09e2b514623a1b3

MDesign

https://forum.onshape.com/discussion/comment/108331#Comment_108331

You have a lot of extra doodads going on in there but I just boolean'd arm back rest and upper back leg then applied a fillet. It has a limit in size of about 4.6mm because the seams on do not meet perfectly (you have to make sure to select that little line shown in pic since its not tangent). and it gets confused at that transition. When in doubt try a tiny fillet. if it works then go bigger and bigger till you find the trouble spot usually highlighted in red. If your sold on face blend. it will probably have the same issues at those points I didn't try face blends. Simple answer is don't waste your energy on creating edges to fillet when boolean or other tools will create those edges for you. So when your loft end is inside the the other part just boolean it together. no need to trim it back to meet up with the other part. Hope that make sense. If not let me know.

jelte_steur814

a face blend is more powerful than a regular fillet operation in some instances. so you could also try that.

dominique_charmot

Mdesign, thanks for trying! I was able to create a fillet on only half of the joint even at 4.6 mm or smaller. I noticed that when an error is shown a pink outline appears that seem to indicate that Onshape is trying to fillet the edge from the inside of the joint not the outside.

MDesign

Pink is good. Means it can probably fillet there. Look for the red to find problem areas.

MDesign

https://forum.onshape.com/discussion/comment/108428#Comment_108428

Also sometimes I'll use a variable fillet in this cases. whatever radius or parameter changes works for the problem area and then larger for the main areas.