Can we use the 3D slicer software only to model the implant?

Can we us the 3d slicer in design of customized implants?

Most probably yes. Can you tell a bit more about what you would like to achieve?

Oh sorry for I lately reply your comment. My project is to make Craniofacial Implants. First of all, I make the model from DICOM File using the grayscale modelmaker. So how can I get the mirror model and locate the defecting skull? Actually, how can I get implants from the healthy side of Craniofacial by using 3d Slicer. Sorry again if it makes you confuse.

There are many tools in Slicer that you can use for surgical planning. For model mirroring you can try Dynamic modeler module:

How can I get the model implant on the red area? How can I subtract it?

What do you mean by getting the model implant on the red area?
What would you like to subtract from what?
What would you like to achieve overall?

Sorry for make you confuse. I want to fill hole the skull and i want only red area in the hole in 3D model. How can i do ? My goal is create a model that is in the hole (red area) in 3D object.

I would make a curve cut with a closed curve in the dynamic modeler on the red model.

Then it can be used as the template to generate the implant you want. There maybe other ways of doing it but i would convert the cut model into segmentation and use the segment editor effects to create/model the implant the way I want.

Once you have the final implant with desired thickness and shape you can use a boolean subtraction (red-yellow) to make the fitting surface to exactly match the defect edges and the skull surface.