<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<div class="container">
<div class="row">
<div class="col">
<div class=" m-4 p-2 bg-faded">
<p class="p-3" style="background-color:#fff">
<button class="btn btn-primary" data-toggle="modal" data-target="#myModalBottom">Launch Demo</button>
</p>
Just add class <code>.modal-bottom</code> to <span class="text-success"><div class="modal-dialog <code>modal-bottom</code>">...</div></span>
</div>
</div>
</div>
</div>
<div class="modal fade" id="myModalBottom" tabindex="-1" role="dialog" aria-labelledby="myLargeModalLabel" style="display: none;" aria-hidden="true">
<div class="modal-dialog modal-bottom">
<div class="modal-content">
<div class="modal-header">
<h4 class="modal-title">Modal Title</h4>
<button type="button" class="close" data-dismiss="modal" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
</div>
<div class="modal-body p-4">
<ul class="list-unstyled">
<li class="media">
<img class="d-flex mr-3" style="background-color:#ccc;width:72px;height:72px" alt="Generic placeholder image">
<div class="media-body">
<h5 class="mt-0 mb-1">List-based media object</h5>
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</div>
</li>
<li class="media my-4">
<img class="d-flex mr-3" style="background-color:#ccc;width:72px;height:72px" alt="Generic placeholder image">