Delete one part of a polygon according to a certain shape

[Anonymous]

Hello, 

I'm pretty new to 3D modeling, and I'm currently stuck at some stage.

I have a box and a spline arc attach to it (see capture1 attached) and I want to delete a part of that face depending on the spline arc shape. 

In the capture2 attached, I want the surface pointed by the blue arrow to be erased and the one pointed by the red arrow to remain. How could I do that ?

Thank you for your answers.

[ads_czechoj]

You need to use a Compound Object => Boolean=>Insert

Steps:

Do not attach anything.

1. Select the "arc" and convert it to the Editable Poly object

2. Select the box

3. From the Modifier Panel =>Geometry=>Compound=> pick the Boolean

4. Add Operands + the Arc

5. Operand Parameters => Insert

6. Add Edit Poly modifier and select the polygon subobject

Result:
The Boolean created intersections between the Arc and the Box.

• Now you can select any part of your model and delete any polygon you wish.

[Anonymous]

Thank you for your precise answer and your video tutorial, it is really helpful. 

Nevertheless, I may have missed something and touched something before, but I followed step-by-step the tutorial and I could not manage to have the same result as you. 

You will find attached what I did, and what results I got.

[ads_czechoj]

OK, there is one more task to do, which I did automatically: you need to move the arc slightly bellow the box. the ark is an open shape (concave shape in this case) and needs to intersect the box.

[irishman_team_kilber]

why not run a connect in the center/centre, and then delete the top poly your bottom poly will remain in tacted? but when you do i think you will find your arc shape to big you will need to make it smaller

[ads_czechoj]

I am not sure what you want to connect to a center.
In order to "cut" a polygon, you have few options in 3dsMax:

Use the cut tool, boolean, slice, etc.

In your case, you need to intersect the arc with the bottom edge of the front polygon and separate faces outside the "gate" and inside the "gate". To do this you need to use the boolean tool which I showed you in my previous post. Good luck! 

[irishman_team_kilber]

but he wants to delete the top poly i think and keep the bottom one from the images he attached, that is the only way to do it unless he uses the cut or the quick slice tool to draw a line,

[Anonymous · Accepted solution]

Sorry for the late answer, I could not tested it before today, but after moving the arc below the box, it perfectly worked. 

Thank you again for your help and your video tutorial.