Color of objects changing when they are joined.

I was trying to model a walking stick using a semi-torus and a cylinder. When I placed them close to each other, this is what I got-


When I joined the semi-torus and the cylinder using Ctrl-J, this is what I see-


As you can notice, the color gradient of the cylinder has changed. Based on the order of selection of the semi-torus and the cylinder, either the cylinder color or the torus color is changing.

I can observe this effect even while modelling and not only during rendering. Material for both the objects is the same.

Why is the joining operation affecting the colors? I am attaching the blend file too for your ref.
Walking_stick.blend (534 KB)

Select all in edit mode and hit ctr+N.

I din’t get you. Can you please elaborate?

what he means is that when you joined the two pieces the direction of your normals was affected, in order for you to fix the problem you need to press the button labled Ctrl on you keyboard whilst at the same time pressing the button marked N (also on your keyboard). this will cause blender to recalculate the normal direction so they all face the same way.
i guess he just didnt want to waste time typing usless info and decided to just give you the solution.
:slight_smile:

Additionally You have very different number of loops in cylinder than in torus. There are also two loops between them, therefore You can´t merge the vertexes perfectly. It causes a small track between torus and cylinder in render.

@Small Troll,
I know all the buttons on the keyboard :slight_smile: Thanks for the info about recalculation of normals! I dint know that :slight_smile:

@marksto
So do you suggest creating the whole stick with a single cylinder and then applying extrude+stretch repeatedly until I get a smooth curve?

But did You fix the the color problem ? or not ?

if you use a single cylinder for the model, you can simply extrude the leangth, then to get the handle select the top edgeloop and use the spin tool to create the curve

@rrtk
Yea, re-calculating normals solved the color problem. Thanks mate :slight_smile:

@Small Troll
I tried the spin tool, though it looks like a walking stick, the handle doesn’t have the same thickness as the body of the stick which is what I wanted (I can vary the body thickness, but still the handle looks like a plate)


It looks more like a tap handle than a walking stick handle. FYI, I selected the top edge loop of the cylinder and applied the spin tool. I guess I am going wrong somewhere!?

ah yes, using the spin tool, you are working with the 3D cursor. if you look at PyroGXPilots post above, you will see the 3D cursor is placed at the center of the diameter of the spin circle (if that makes sense?)

you must be in orthographic view with the view set either front or side as the viewing angle defines the angle of the spin. (1 or 3 on numberpad. 5 to switch between ortho and perspective)
ensure that your scale is set to 1 in object mode (ctrl A) then click spin in the tool bar and adjust the tool options to;
steps 9 (less than 9 gives a less smooth curve, more give a smoother curve)
angle 180 and you should get a similar result as PyroGXPilot.

@Small Troll, @PyroGXPilot
Thanks both of you, I finally got it :slight_smile: 3D cursor placement was the problem and its now fine.