Once in awhile you have to check for stray "vertices," and delete these. They usually show up in the 2d viewport as red dots as shown in Figure 1.10. Just simply press the "Delete" key on your "keyboard," to get rid of these.
Figure 1.10 Stray Vertices from previous Delete
Switch to the "Materials" rollout. Select the material for the op4 knife called "knife_blade.bmp" in the list area. Click the "Delete" button as shown in Figure 1.11.
Figure 1.11 Deleting the unnecessary Materials
If you would like to use the op4 skeleton for viewing your knife as attached to a model. you could do as described in the next paragraph. We will be creating our own skeleton though. I am just going to step you through how to use an existing skeleton so that in the future you will not have to create a new skeleton each time.The first step for making the "p_knife2.mdl" will be exactly the same as we just have done in the paragraphs preceding this, even if you are going to create your own biped.