How to seamlessly merge junction of different shapes with gradients?

Question

In Inkscape I'm creating a 3D cube like shape with some curvature along the border edges. To simulate the curvature I'm using two adjacent paths with linear gradients facing opposite direction, like a bilinear gradient.

But how do I merge this junction point seamlessly along the corner curve? Blurring the paths reduces the seam a bit, but also makes the paths bloom outside the boundary of the cube. Is it possible to create a gradient along a path?

Answer 1

I'm sure there are many ways this could be done, but here's one method:

Create a single Y shape to cover the corners you wish to apply a highlight to, and fill it with white or light grey. In the fill panel, apply some blur to it, then copy and paste the polygon shape in place using Edit > Paste in Place - then apply that as a clipping mask to the blurred Y, using Object > Clip > Set.

Answer 2

I`d go for...

• Union of all of the existing elements (with gradients, from your drawing);
• add a few nodes to create smoother curvature of the "crossing" at the centre;
• create the mask or clip in the shape of the cube, bring it to the top;
• blur the shape from the Union operation and mask/clip it.

Or...

• create three squares/rectangles with slightly rounded corners matching the edges of the cube;

• only two sides of each rectangle are matching the edges and the other two are "outside" of the cube. In other words, new rectangles are larger than sides of the cube;

• might be easier if you use rectangles with rounded corners, disable stroke scaling and then skew or otherwise modify rectangles.

• set the white thicker Stroke and blur it.

• add a shape which would fill the gap between the
• once again, use the shape of the cube as the mask/clip

Answer 3

I'd actually do this a different way, with interpolation. That will give you a lot more control over the shapes. This is a very rough example done with illustrator, but you should be able to achieve the same results with inkscape:

https://www.evernote.com/l/AAEXKjNIuCtELbC5fRwki3pV6mn-zkt32v4B/image.png