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When you first add a cylinder, you have the option to change the number of vertices, etc, but once you do anything else in blender, it seems you no longer can edit those parameters.

Is there a setting anywhere or an add-on that allows these parameters to be edited later on? If not, how easy would such an addon/feature be to create for anyone reading this?

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Blender does not have a construction history. You can only edit the parameters of the last action, nothing earlier than that.

To edit the parameters of the last action you can either use F9, you can go to Edit > Adjust Last Operation or open up the panel on the bottom left of the 3d Viewport.

enter image description here enter image description here

If you want to modify the last tool you have to do it before using another tool.


In Blender 2.7x you can use F6 or the Operator Tab in the Tool Panel T to edit the parameters of the last action.

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    $\begingroup$ It seems like that could be something that could be implemented maybe through the same mechanism the Undo history is recorded, but then again, I'm not a developer. $\endgroup$ – Thom Blair III Mar 18 '14 at 13:04
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There is a workflow solution to this. While you're making a model, if you think that you may want to change one or more parts of the model, make that set of parts separate bits of the mesh. This can be achieved with a vertex group, or just by leaving the part of the mesh unconnected to the rest of the object.

When you decide to select on part, select it by using the defined vertex group, or if you've left it unconnected to the rest of the mesh, by selecting a point on the part and pressing CTRL - L, or by pressing CTRL [numpad] + until the part is selected. Get the necessary parameters of the part (especially the median point location), or create the new one, if not at the desired location, in a way that you can move it there, and when it is in the desired place delete the original.

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As already mentioned in other answers you can't edit object options after they are created. We don't have native "parametric primitives" in Blender yet, after the creation process they become regular "static" objects and loose any adjustable properties they had.

In an attempt to not leave you empty handed I'll try to present an alternative workflow: Be smart, use modifiers to your advantage.

If you foresee the need to adjust geometry after the fact, or edit parameters frequently, plan ahead, build your objects in a way that allows tweaking needed parameters easily.

This is where modifiers come in, they provide what is often called "non-destructive modeling."

If you need to, say, easily change the number segments of a cylinder, or frequently adjust its height then it would be smart to rather than of adding a regular mesh cylinder build one from scratch with modifiers instead.

Create a simple single vertex mesh with no actual faces whatsoever, add a Screw Modifier to it, then a Solidify Modifier. You now have a "Parametric Cylinder" you can easily adjust the number of segments and height of.

enter image description here

Just control parameters from the modifier stack. Height from the Solidify Thickness and segments from the Screw Steps. Replace the single vertex with an edge extending to the local origin and now you have top and bottom caps.

This is what is often called a "non-destructive workflow", where modifiers are kept "live" so they can be easily edited.

This will obviously not work every time nor for everything, and you can't always achieve every end goal without some destructive steps (like applying some modifiers), but be inventive and you can go a long way.

Use modifiers to your advantage, extend this to other tools like constrains, drivers, shapekyes etc., and you can go a long way in creating easily editable "parametric objects".

Here is a "Parametric Sphere" made from a single vertex mesh and two Screw modifiers.

enter image description here

You could even control radius with an additional Displace Modifier

A parametric 2D circle with inner and outer radius.

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    $\begingroup$ I am very new to blender. I love the globe example using the screw modifier, There isn't a hope in Hades I would have thought of that myself. Thankyou $\endgroup$ – DeveloperChris Feb 26 at 0:53
  • $\begingroup$ Nice! I think Blender could implement parametric sphere, cylinder and cube this way by default. $\endgroup$ – Mikko Rantalainen Oct 3 at 15:38
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With Blender 2.8 at least, you can always hit the F9 key and you´ll see the operator panel again.

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    $\begingroup$ Thanks! This is exactly what I was looking for. I would add that you cannot bring up the operator panel again once you go into edit mode with that object or move it with the mouse. It would be nice to maybe have a parametric object type available that can be converted into a mesh later, or maybe a given a mesh modifier for non-destructive editing. $\endgroup$ – Coby Randal Jan 23 at 4:48
  • $\begingroup$ I am new to blender and this seems a bit insane to be because, it also seems that I cannot make a new primitive at anywhere other than the origin. So what happens if my origin is already occupied by other geometry and I cannot see the new shape? I can do the "Adjust Last Operation" right after creating the object, but then I can't easily see what effect changing the parameters has because the geometry is not visible. Is there a workaround for this? $\endgroup$ – uglycoyote Feb 8 at 21:39
  • $\begingroup$ @uglycoyote You can create your new item at the cursor. On the lower left the operator properties will appear (might be collapsed). In them, you can usually change the spawn point. This will undo the creation and redo it at the updated position, keeping the other settings intact. As for setting parameters after the fact: It is only possible by bundling the properties into the mesh/object. Only a few addons do this for their custom objects. After creating the object, the parameters are stored in the object. Later on a button allows to rebuild the object from these parameters. $\endgroup$ – Teck-freak Oct 13 at 3:14

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