Blender 2.49b IK Solver Constraints Panel

I am running Blender 2.49b with Vista Home Premium 32 bit and SP2. I am working my way (slowly) through Ryan Dale’s Introductgion to Character Animation. I have got stuck with the IK Solver constraints panel. When I type a bone name in the BO target box (and in the BO pole target box) the name disappears as soon as I press enter. What am I doing wrong?

Best wishes

Tony Holland

That means no object with that name exists. make sure you are spelling it correctly with the proper case as well. it drives me up the wall, one reason why i’m excited about 2.5 (in 2.5 if you click a field to enter an object name a drop down listbox appears so you can just select it from the list! so simple, yet took so long to get right! ;)) hope this helps.

Thanks Wysiwyg but I think it must be something else. I’ve checked and double checked my spelling but it still won’t work. I’ve attached the blender file, which I hope will help identify the error. Best wishes

Tony Holland


AnimTut316.blend (264 KB)

Hi Tony,

I looked at your file, and it worked fine for me. I see you are trying to add an IK constraint to ‘lower_leg.l’ so I will offer a few tips to hopefully help you out.

First off, don’t even concern yourself with the ‘Pole Target:’ portion of the constraint. It’s a feature that was added after that tutorial was written, and Ryan uses a different constraint to accomplish the same effect. Just focus on the ‘Target:’ portion of the constraint.

Since you are having trouble with the ‘BO:’ field I assume you are entering the ‘OB:’ name correctly, or you wouldn’t see the ‘BO:’ box. It only opens up after you enter the name of your rig in the ‘OB:’ field. But here is a tip, under ‘Target:’ in the ‘OB:’ field you can start to type the name of your armature and hit the tab key and blender will insert the name. In your case, your armature is named ‘Bones’, so you enter ‘Bon’ in the ‘OB:’ field and hit the tab key and blender will finish the name for you.

Now the ‘BO:’ field will appear. This is where you want to type the name of the bone that will control the IK constraint. In your case, you want to enter ‘leg.l’ or you can select the bone you want with the left mouse button. Then look for the ‘Armature Bones’ panel. Right under ‘Selected Bones’ you will see a field call ‘OB:’ hover the mouse in that field and hit Ctrl-C. Select the lower_leg.l bone again with the left mouse button, move the mouse over the ‘BO:’ field and hit Ctrl-V and blender will insert the name.

When I did this to your file, the armature twisted a bit. To correct that, click on the ‘Use Tail’ button below the ‘BO:’ field.

I did the same tutorial, and it is an excellent tutorial. I hope this fixes your problems, if not, let me know.


Great work, Randy, many thanks. I hadn’t realised the armature is called Bones - so much for being a newbie!

Best wishes for Christmas and the New Year

Tony Holland

By default, an armature’s name is ‘Armature’ when created, so I am thinking you must have renamed it somewhere along the way. It’s an easy thing to do with so many buttons and fields in blender, I still do it myself. Glad I helped.

Have a Merry Christmas and a Happy New Year!!!