Curving a Rectangle by 90 Degrees

Hi All,
I have been coming to this forum for several years now. I finally joined a couple of days ago, so, I am not really new but this is my first post. Anyhow, on to the problem.
Imagine facing a rectangular frame on a horizontal plane. The goal is to bend the frame 90 degrees without causing distensia or distortion to its guts. At this time I don’t feel that the measurement of the radius is relavant however, in the event that it is, providing that my math is correct, the radius is 21 29/32" on the inside of the curve and 24 3/4" on the outside of the curve.
I have read through everything I can find in these forums and even tried hands-on with that information but, to no avail. I have tried to parent curves, build on curves, build with curves, and add curve modifyers all with terrible results. It is not something that can be extruded on a curve because there will be a design on the interior of the frame.
The only solution I have been able to come up with is to build the rectangular frame on the curve, then add the innerds. But, the problem with this is the lack is precisioned detail. Because of the lack of refernce points ( grid ), I subdivided the curved frame several times and then used the geometry of those vertices to apply my pattern. Sound like it worked? Not hardly. The reason is that when rendered, it looks like H3LL. Especially when you move it farther back for the camera. The details inside the frame are not too small because it is to scale with the rest of the piece. Upon this failure, I decided that it might be more practical to build the pattern inside a squared rectangular frame and then bend it to meet the curve. I have worked on this for several days and at this point am being counterproductive and decided it was time to ask for help.
All comments and suggestions are welcome.
Thanks for your time, Daniel

K, do you mean like a picture frame where you’d want it to bend 90 degrees around a pole without the picture distorting?

Sorry, having a hard time visualizing.

Similar to that. Try to visualize a sphere facing on the same plane as the rectangle and wrap the rectangle 1/4 of the way around the sphere on a flat plane. Hope this helps.
Thanks, Daniel

K, I think your building the rectangular frame along the curve idea was a winner. Why does it look like h3ll ? Sounds like a problem there we can fix rather than abandoning the idea. I can use the To Sphere function on a heavily subdivided plane, extrude the plane up to make it a box, work it a bit to make it look like a picture frame and it looks perfect.

I have tried the to sphere function with out reasonable reasults. The problem with extruding is the pattern on the inside of the frame will be destroyed. If it helps, visualise the inside of the frame with a fretwork or relief mesh connected. This mesh is what I want to Not distort.

Ok, seems to me that yo need to add the guts later if you don’t want them to warp. If you’re curving them with the frame then they will if there’s any height to them.

This is how I did this so far. I made a rectangular plane and subdivided it heavily. Then I extruded that up a bit, hit x and removed the top faces so it was an empty box. Then I added a cube and extruded it sideways and up and down so I had a plus sign and put this in the middle of the box.

Then I added a Path in top view and scaled it on the x axis so it was the same width as the box. Select box, then Path, then hit Cnrtl+P and selected curve deform. With the Path selected in edit buttons I had Curve Path and Curve extend selected and turned off Curve Follow. With the box selected in anim buttons I hit the big Track X.

Now I went into edit mode on the path in front view and moved the 4 outside control points down so they formed an arch. Then to finish I selected the box and hit Make Real, then Apply in the modifiers.

Anyway that was it. The box cross in the middle looked good, but was a bit deformed. Subdividing them alot helped. And to get the spherical curving, I just added a path along the Y axis and repeated the process from side view.

I tried warp, but it seems to want to warp the normals too and they get to be sticking out at weird angles.

BINGO ! !, Your last observation was definitely on the right track Enzoblue. I also discovered trough the course of trying your solution that, IF you subdivide the outside of the frame several times, and turn on the proportional editing with the smooth falloff, the lines will not cross one another and it will give more control to the object and less distortion to its innerds.
We shall call this the immediate solution, BUT, would like to hear some solutions from other users.

Thankyou Enzoblue for your time, effort and Solution to such a daunting task.