Hi folks,
I'm fairly new to Fusion and am looking for a bit of advice. I'm trying to use the patch tool to create a surface. When I select the boundary edges the new surface appears (see first screengrab below). However when I then click OK the surface disappears and I get the error message shown below. Any advice on what I am doing wrong would be greatly appreciated!
@Anonymous, can you share the model here? That behavior seems like a bug, and we'd like to investigate it further.
thanks!
Hi Jeff,
Thanks for responding. The starting point for this model is an .Iges file from a client. I am unable to share this with you as it is a model of their product.
I have managed to track the problem down to two of the boundary edges forming the patch. I then I created a sketch and used the Include 3D Geometry tool to capture all of the edges for the patch then replaced two of the edges in the 3D sketch with splines that closely followed the problem edges. I was then able to use this 3D sketch to successfully create a patch. This patch could then be stitched relatively well with the rest of the model - although not perfectly as the curvature analysis below shows. I believe this must be due to differences between the new splines and the actual curve of the edge.
So it seems that perhaps the edges of the surfaces from the .Iges file were tripping Fusion up when trying to make the patch. What are your thoughts?
Thanks,
Nils
@Anonymous, it is a little hard to speculate what might be going on without the model itself, but I understand the limitation in what you can share with us. It may be that the model edges in the IGES file are not precisely aligned, within some tolerances, and that trying to Patch from that data fails because of those small inaccuracies. It could be a bug in Fusion or the modeling kernel.
Your method of using the Include 3D Geometry command might well smooth over enough of the inaccuracies that lets it succeed. There is some approximation involved from edge to sketch curve. The problem of not getting good results could be a number of issues. It could be the approximation converting to a sketch curve. But, also, when doing a Patch from sketch curves, you cannot leverage the adjacent surfaces for tangency conditions.
