When modeling curved tubes in BikeCAD, although you are allowed to input any amount of deflection and any value of curve radius you like. It's not always physically possible to create a tube with those properties.
In the example above you can tell by the artifacts extending from the down tube that we likely have a problem here.
A new feature in BikeCAD Pro Version 8 helps us resolve these issues. When we click on the problem curves icon, BikeCAD connects the reference points of our curved tube with dashed lines to help us visualize the geometry of our tube. It also highlights the curved sections in green or red. Red markings identify cases where there simply isn't enough room to fit the requested radius.
There are several possible solutions to a problem like this. For example, you could lengthen the tube. Alternatively, you could reduce the amount of deflection. Or finally, you could reduce the radius of the curve. Because there is more than one way to resolve this issue, BikeCAD leaves it up to you to change the geometry. However, once you've got something that fits, BikeCAD will display the radiused section in green.
Once you're satisfied with your design, you can turn off the colouration by unselecting the problem curves icon.