HiNC-2025-win-desktop-Deploy/App/wwwroot/HiAPI-docsite/technique/simulation-performance/mesh-resolution.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
      <title>Mesh Resolution | HiAPI-C# 2025 </title>
      <meta name="viewport" content="width=device-width, initial-scale=1.0">
      <meta name="title" content="Mesh Resolution | HiAPI-C# 2025 ">
      
      
      <link rel="icon" href="../../img/HiAPI.favicon.ico">
      <link rel="stylesheet" href="../../public/docfx.min.css">
      <link rel="stylesheet" href="../../public/main.css">
      <meta name="docfx:navrel" content="../../toc.html">
      <meta name="docfx:tocrel" content="toc.html">
      
      <meta name="docfx:rel" content="../../">
      
      
      
      <meta name="loc:inThisArticle" content="In this article">
      <meta name="loc:searchResultsCount" content="{count} results for &quot;{query}&quot;">
      <meta name="loc:searchNoResults" content="No results for &quot;{query}&quot;">
      <meta name="loc:tocFilter" content="Filter by title">
      <meta name="loc:nextArticle" content="Next">
      <meta name="loc:prevArticle" content="Previous">
      <meta name="loc:themeLight" content="Light">
      <meta name="loc:themeDark" content="Dark">
      <meta name="loc:themeAuto" content="Auto">
      <meta name="loc:changeTheme" content="Change theme">
      <meta name="loc:copy" content="Copy">
      <meta name="loc:downloadPdf" content="Download PDF">

      <script type="module" src="./../../public/docfx.min.js"></script>

      <script>
        const theme = localStorage.getItem('theme') || 'auto'
        document.documentElement.setAttribute('data-bs-theme', theme === 'auto' ? (window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light') : theme)
      </script>

  </head>

  <body class="tex2jax_ignore" data-layout="" data-yaml-mime="">
    <header class="bg-body border-bottom">
      <nav id="autocollapse" class="navbar navbar-expand-md" role="navigation">
        <div class="container-xxl flex-nowrap">
          <a class="navbar-brand" href="../../index.html">
            <img id="logo" class="svg" src="../../img/HiAPI.logo.png" alt="">
            
          </a>
          <button class="btn btn-lg d-md-none border-0" type="button" data-bs-toggle="collapse" data-bs-target="#navpanel" aria-controls="navpanel" aria-expanded="false" aria-label="Toggle navigation">
            <i class="bi bi-three-dots"></i>
          </button>
          <div class="collapse navbar-collapse" id="navpanel">
            <div id="navbar">
              <form class="search" role="search" id="search">
                <i class="bi bi-search"></i>
                <input class="form-control" id="search-query" type="search" disabled placeholder="Search" autocomplete="off" aria-label="Search">
              </form>
            </div>
          </div>
        </div>
      </nav>
    </header>

    <main class="container-xxl">
      <div class="toc-offcanvas">
        <div class="offcanvas-md offcanvas-start" tabindex="-1" id="tocOffcanvas" aria-labelledby="tocOffcanvasLabel">
          <div class="offcanvas-header">
            <h5 class="offcanvas-title" id="tocOffcanvasLabel">Table of Contents</h5>
            <button type="button" class="btn-close" data-bs-dismiss="offcanvas" data-bs-target="#tocOffcanvas" aria-label="Close"></button>
          </div>
          <div class="offcanvas-body">
            <nav class="toc" id="toc"></nav>
          </div>
        </div>
      </div>

      <div class="content">
        <div class="actionbar">
          <button class="btn btn-lg border-0 d-md-none" type="button" data-bs-toggle="offcanvas" data-bs-target="#tocOffcanvas" aria-controls="tocOffcanvas" aria-expanded="false" aria-label="Show table of contents">
            <i class="bi bi-list"></i>
          </button>

          <nav id="breadcrumb"></nav>
        </div>

        <article data-uid="Technique-MeshResolution">
          <h1 id="mesh-resolution">Mesh Resolution</h1>

<p><a class="xref" href="../../api/Hi.MachiningProcs.SessionShell.html#Hi_MachiningProcs_SessionShell_MachiningResolution_mm">MachiningResolution_mm</a> is the edge length of the cubes the
workpiece is built from, and it is the single largest lever on how long a simulation takes. It is
also the setting most often set once and forgotten, which is expensive in both directions: too
fine and a run that should take minutes takes hours, too coarse and a feature the program is
supposed to cut is not there to be cut.</p>
<h2 id="choosing-a-value">Choosing a Value</h2>
<p>Work coarse first. An early run answers questions — does the path collide, is the force roughly
where it should be, does the optimizer have room — that do not need a fine mesh, and it answers
them in a fraction of the time. Refine only for the final optimization pass, where the geometry
that comes out is the deliverable.</p>
<p>As a planning figure, a simulation run takes somewhere between <strong>2% and 150% of the actual
machining time</strong>, spanning that whole range depending on the mesh and the step count. That is
wide because it is genuinely a choice, not a property of the machine.</p>
<p>Where the time actually goes, and which of the two costs is currently the bottleneck, is in
<a href="cpu-usage.html">CPU Usage During Simulation</a>. The short version: at the fine resolutions real NC
work needs, geometry removal dominates and a finer mesh is much slower; once the mesh is coarse
enough that removal is cheap, the per-step costs dominate and coarsening further buys nothing.</p>
<h2 id="what-value-you-actually-get">What Value You Actually Get</h2>
<p>The number you type is a request, not the width. The workpiece is carved out of a cube grid that
starts from one fixed root cube and is halved level by level, so every width the engine can
actually build is a power of two in millimetres:</p>
<pre><code>... 2 - 1 - 0.5 - 0.25 - 0.125 - 0.0625 - 0.03125 ...
</code></pre>
<p>A request that is not one of those is rounded <strong>to the next finer one</strong>, never to a coarser one,
so the mesh you get is never worse than the mesh you asked for. The consequence worth knowing is
that a value chosen off the ladder buys nothing:</p>
<table>
<thead>
<tr>
<th>Requested</th>
<th>Actually built</th>
</tr>
</thead>
<tbody>
<tr>
<td>0.5</td>
<td>0.5</td>
</tr>
<tr>
<td>0.4</td>
<td>0.25</td>
</tr>
<tr>
<td>0.3</td>
<td>0.25</td>
</tr>
<tr>
<td>0.25</td>
<td>0.25</td>
</tr>
<tr>
<td>0.2</td>
<td>0.125</td>
</tr>
<tr>
<td>0.125</td>
<td>0.125</td>
</tr>
</tbody>
</table>
<p><strong>0.4 mm and 0.25 mm produce the same mesh, at the same cost.</strong> 0.4 is 0.25 wearing a misleading
label: it reads as a coarse, cheap setting and runs as a fine, expensive one. If 0.25 mm is finer
than the run needs, the next value that changes anything is 0.5 mm — and going the other way,
0.125 mm is another eight times the voxels, not a small step.</p>
<p>The ladder bottoms out at <strong>0.001953125 mm</strong>. A finer request is clamped to it, so the finest entry
offered in the workpiece's Initial Resolution list builds the same mesh as the one above it.</p>
<h2 id="the-width-only-ever-goes-finer">The width only ever goes finer</h2>
<p>A mesh that exists cannot be coarsened. Every cut takes the <strong>finer</strong> of the width already built and
the width being asked for, so raising Machining Resolution above the mesh the workpiece was built at
does not simplify anything — the request is dropped and the run keeps the mesh it has.</p>
<p>This is why the two settings are not interchangeable. The workpiece's <strong>Initial Resolution</strong> is what
builds the mesh and is therefore the memory setting; <strong>Machining Resolution</strong> gates how fine a
<em>newly cut</em> surface may go, and can only ever refine. To make a run cheaper in memory, coarsen the
Initial Resolution — coarsening Machining Resolution alone changes nothing about the stock that is
already there.</p>
<p>It still changes the <em>time</em>, and by a lot, because the same number sizes two other things: the
tessellation of the cutter's own solid, and the number of engagement layers per step. Both are
per-step work that is thrown away again, so a coarser Machining Resolution can cut the run time
several-fold while the memory figure does not move at all. A run that got faster without getting
smaller is this, not a mystery.</p>
<p>Pick from the ladder and the number shown in the mission row is the number the run used. That
matters beyond tidiness: a recorded mesh is built at whatever resolution is in force when the
record runs, so an off-ladder value is silently baked into the cache as its rounded neighbour.</p>
<h2 id="what-it-costs-in-memory">What It Costs in Memory</h2>
<p>Far less than it costs in time, which is the opposite of what four rungs of the ladder — sixteen
times finer, and so four thousand times the voxels — leads most people to expect. Measured by
sweeping one case across five rungs with the program and the step count held fixed — a cylindrical
blank, one roughing program, 199,242 steps every run:</p>
<table>
<thead>
<tr>
<th>Mesh width</th>
<th>Play time</th>
<th>Process memory outside the managed heap</th>
</tr>
</thead>
<tbody>
<tr>
<td>2 mm</td>
<td>10.5 s</td>
<td>665 MB</td>
</tr>
<tr>
<td>1 mm</td>
<td>15.3 s</td>
<td>688 MB</td>
</tr>
<tr>
<td>0.5 mm</td>
<td>31.2 s</td>
<td>722 MB</td>
</tr>
<tr>
<td>0.25 mm</td>
<td>76.6 s</td>
<td>826 MB</td>
</tr>
<tr>
<td>0.125 mm</td>
<td>242.9 s</td>
<td>1,456 MB</td>
</tr>
</tbody>
</table>
<p>Sixteen times finer costs <strong>23 times the time and 2.2 times the memory</strong>. Two things flatten that
second column, and it is worth separating them:</p>
<ul>
<li><strong>Most of the figure is a baseline the mesh does not set.</strong> The coarsest run in the sweep already
sits at 665 MB, and the whole sixteen-fold refinement adds 791 MB on top of it. Read the column as
increments rather than as totals: the ratio at the bottom of the table is diluted by everything in
the figure that would be there at any mesh width.</li>
<li><strong>The increments grow slowly at coarse widths and then accelerate.</strong> Halving the width added
23 MB, then 34, then 104, then 630 — each increment about 1.5, then 3.1, then 6.1 times the one
before it, a local exponent climbing from roughly 0.6 to 2.6. A cube stops subdividing as soon as
the surface inside it is a single flat facet, so while the mesh is coarser than the part's facets
and curvature, refining mostly buys nothing. The volume-scaling intuition is not wrong; it only
arrives once the width is below the feature scale, and by then it arrives fast.</li>
</ul>
<p>A big <em>workpiece</em> moves the same curve up: where the stock is a large imported solid rather than a
small procedural blank, there is far more surface to subdivide and the mesh-dependent part dominates
much earlier.</p>
<p><strong>Do not judge the mesh by the process's peak memory.</strong> On a long run most of that figure is the
per-step data the run accumulates, which lives on the managed heap, scales with the number of steps
and not with the mesh at all — and it moves the <em>other</em> way when the mesh is refined, because a
slower run allocates more slowly and the collector commits less. The two cancel: measured on a
larger case across a four-fold refinement, peak memory fell slightly while the mesh's own footprint
grew by nearly 40%. Read the two apart before concluding anything.</p>
<h2 id="what-the-mesh-does-not-change">What the Mesh Does Not Change</h2>
<p>For a representative test case — downward circular slot milling with varying width and depth —
the <strong>physical</strong> values move within about <strong>20%</strong> across the full range of mesh widths. The
simulated forces, torques and temperatures from a coarse first pass are therefore already
informative; they do not become a different answer when the mesh is refined.</p>
<p>The visible geometry is a different matter, and it is what the three runs below show. Workpiece
70 × 50 × 50 mm:</p>
<p><img src="mesh-resolution-img/mesh-width-0125.png" alt="Mesh width 0.125 mm">
Mesh width 0.125 mm</p>
<p><img src="mesh-resolution-img/mesh-width-05.jpg" alt="Mesh width 0.5 mm">
Mesh width 0.5 mm</p>
<p><img src="mesh-resolution-img/mesh-width-1.png" alt="Mesh width 1 mm">
Mesh width 1 mm</p>
<h2 id="the-failure-mode-worth-knowing">The Failure Mode Worth Knowing</h2>
<p><strong>A thin shell thinner than the mesh width can disappear entirely.</strong> The test case above has no
thin shell, which is why its physical values are so insensitive; a part that does have one behaves
differently, because the material the cutter should be meeting is not represented at all. Where
the workpiece has a wall, web or floor thinner than the mesh width, the mesh must be finer than
that feature before the run says anything about it.</p>
<p>The related and much smaller effect is quantization ripple in the per-step ratios, which a finer
mesh reduces — see <a class="xref" href="../milling-physics/machinability.html">Process Machinability</a>.</p>
<h2 id="see-also">See Also</h2>
<ul>
<li><a href="cpu-usage.html">CPU Usage During Simulation</a> — which of the two cost drivers a given mesh width puts in the way</li>
<li><a class="xref" href="../milling-physics/machinability.html">Process Machinability</a> — the mesh-quantization ripple in the availability ratios, and why it is an artifact rather than a signal</li>
<li><a href="../../manual/setup/workpiece.html">Workpiece</a> — where the initial resolution is set, on the branch carrying the stock it applies to</li>
</ul>

</article>

        <div class="contribution d-print-none">
        </div>

        <div class="next-article d-print-none border-top" id="nextArticle"></div>

      </div>

      <div class="affix">
        <nav id="affix"></nav>
      </div>
    </main>

    <div class="container-xxl search-results" id="search-results"></div>

    <footer class="border-top text-secondary">
      <div class="container-xxl">
        <div class="flex-fill">
          <span> Copyright © 2025 <a href='https://superhightech.com.tw'>Tech Coordinate</a>. All rights reserved. <a href='https://superhightech.com.tw'>超級高科技股份有限公司</a> © 2025 版權所有 </span>
        </div>
      </div>
    </footer>
  </body>
</html>